gpu: host1x: Fix a use of uninitialized mutex

In the Linux kernel, the following vulnerability has been resolved:

gpu: host1x: Fix a use of uninitialized mutex

commit c8347f915e67 ("gpu: host1x: Fix boot regression for Tegra")
caused a use of uninitialized mutex leading to below warning when
CONFIG_DEBUG_MUTEXES and CONFIG_DEBUG_LOCK_ALLOC are enabled.

[ 41.662843] ------------[ cut here ]------------
[ 41.663012] DEBUG_LOCKS_WARN_ON(lock->magic != lock)
[ 41.663035] WARNING: CPU: 4 PID: 794 at kernel/locking/mutex.c:587 __mutex_lock+0x670/0x878
[ 41.663458] Modules linked in: rtw88_8822c(+) bluetooth(+) rtw88_pci rtw88_core mac80211 aquantia libarc4 crc_itu_t cfg80211 tegra194_cpufreq dwmac_tegra(+) arm_dsu_pmu stmmac_platform stmmac pcs_xpcs rfkill at24 host1x(+) tegra_bpmp_thermal ramoops reed_solomon fuse loop nfnetlink xfs mmc_block rpmb_core ucsi_ccg ina3221 crct10dif_ce xhci_tegra ghash_ce lm90 sha2_ce sha256_arm64 sha1_ce sdhci_tegra pwm_fan sdhci_pltfm sdhci gpio_keys rtc_tegra cqhci mmc_core phy_tegra_xusb i2c_tegra tegra186_gpc_dma i2c_tegra_bpmp spi_tegra114 dm_mirror dm_region_hash dm_log dm_mod
[ 41.665078] CPU: 4 UID: 0 PID: 794 Comm: (udev-worker) Not tainted 6.11.0-29.31_1538613708.el10.aarch64+debug #1
[ 41.665838] Hardware name: NVIDIA NVIDIA Jetson AGX Orin Developer Kit/Jetson, BIOS 36.3.0-gcid-35594366 02/26/2024
[ 41.672555] pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 41.679636] pc : __mutex_lock+0x670/0x878
[ 41.683834] lr : __mutex_lock+0x670/0x878
[ 41.688035] sp : ffff800084b77090
[ 41.691446] x29: ffff800084b77160 x28: ffffdd4bebf7b000 x27: ffffdd4be96b1000
[ 41.698799] x26: 1fffe0002308361c x25: 1ffff0001096ee18 x24: 0000000000000000
[ 41.706149] x23: 0000000000000000 x22: 0000000000000002 x21: ffffdd4be6e3c7a0
[ 41.713500] x20: ffff800084b770f0 x19: ffff00011841b1e8 x18: 0000000000000000
[ 41.720675] x17: 0000000000000000 x16: 0000000000000000 x15: 0720072007200720
[ 41.728023] x14: 0000000000000000 x13: 0000000000000001 x12: ffff6001a96eaab3
[ 41.735375] x11: 1fffe001a96eaab2 x10: ffff6001a96eaab2 x9 : ffffdd4be4838bbc
[ 41.742723] x8 : 00009ffe5691554e x7 : ffff000d4b755593 x6 : 0000000000000001
[ 41.749985] x5 : ffff000d4b755590 x4 : 1fffe0001d88f001 x3 : dfff800000000000
[ 41.756988] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000ec478000
[ 41.764251] Call trace:
[ 41.766695] __mutex_lock+0x670/0x878
[ 41.770373] mutex_lock_nested+0x2c/0x40
[ 41.774134] host1x_intr_start+0x54/0xf8 [host1x]
[ 41.778863] host1x_runtime_resume+0x150/0x228 [host1x]
[ 41.783935] pm_generic_runtime_resume+0x84/0xc8
[ 41.788485] __rpm_callback+0xa0/0x478
[ 41.792422] rpm_callback+0x15c/0x1a8
[ 41.795922] rpm_resume+0x698/0xc08
[ 41.799597] __pm_runtime_resume+0xa8/0x140
[ 41.803621] host1x_probe+0x810/0xbc0 [host1x]
[ 41.807909] platform_probe+0xcc/0x1a8
[ 41.811845] really_probe+0x188/0x800
[ 41.815347] __driver_probe_device+0x164/0x360
[ 41.819810] driver_probe_device+0x64/0x1a8
[ 41.823834] __driver_attach+0x180/0x490
[ 41.827773] bus_for_each_dev+0x104/0x1a0
[ 41.831797] driver_attach+0x44/0x68
[ 41.835296] bus_add_driver+0x23c/0x4e8
[ 41.839235] driver_register+0x15c/0x3a8
[ 41.843170] __platform_register_drivers+0xa4/0x208
[ 41.848159] tegra_host1x_init+0x4c/0xff8 [host1x]
[ 41.853147] do_one_initcall+0xd4/0x380
[ 41.856997] do_init_module+0x1dc/0x698
[ 41.860758] load_module+0xc70/0x1300
[ 41.864435] __do_sys_init_module+0x1a8/0x1d0
[ 41.868721] __arm64_sys_init_module+0x74/0xb0
[ 41.873183] invoke_syscall.constprop.0+0xdc/0x1e8
[ 41.877997] do_el0_svc+0x154/0x1d0
[ 41.881671] el0_svc+0x54/0x140
[ 41.884820] el0t_64_sync_handler+0x120/0x130
[ 41.889285] el0t_64_sync+0x1a4/0x1a8
[ 41.892960] irq event stamp: 69737
[ 41.896370] hardirqs last enabled at (69737): [<ffffdd4be6d7768c>] _raw_spin_unlock_irqrestore+0x44/0xe8
[ 41.905739] hardirqs last disabled at (69736):
---truncated---