PM / devfreq: rk3399_dmc: Disable edev on remove()

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

PM / devfreq: rk3399_dmc: Disable edev on remove()

Otherwise we hit an unablanced enable-count when unbinding the DFI
device:

[ 1279.659119] ------------[ cut here ]------------
[ 1279.659179] WARNING: CPU: 2 PID: 5638 at drivers/devfreq/devfreq-event.c:360 devfreq_event_remove_edev+0x84/0x8c
...
[ 1279.659352] Hardware name: Google Kevin (DT)
[ 1279.659363] pstate: 80400005 (Nzcv daif +PAN -UAO -TCO BTYPE=--)
[ 1279.659371] pc : devfreq_event_remove_edev+0x84/0x8c
[ 1279.659380] lr : devm_devfreq_event_release+0x1c/0x28
...
[ 1279.659571] Call trace:
[ 1279.659582] devfreq_event_remove_edev+0x84/0x8c
[ 1279.659590] devm_devfreq_event_release+0x1c/0x28
[ 1279.659602] release_nodes+0x1cc/0x244
[ 1279.659611] devres_release_all+0x44/0x60
[ 1279.659621] device_release_driver_internal+0x11c/0x1ac
[ 1279.659629] device_driver_detach+0x20/0x2c
[ 1279.659641] unbind_store+0x7c/0xb0
[ 1279.659650] drv_attr_store+0x2c/0x40
[ 1279.659663] sysfs_kf_write+0x44/0x58
[ 1279.659672] kernfs_fop_write_iter+0xf4/0x190
[ 1279.659684] vfs_write+0x2b0/0x2e4
[ 1279.659693] ksys_write+0x80/0xec
[ 1279.659701] __arm64_sys_write+0x24/0x30
[ 1279.659714] el0_svc_common+0xf0/0x1d8
[ 1279.659724] do_el0_svc_compat+0x28/0x3c
[ 1279.659738] el0_svc_compat+0x10/0x1c
[ 1279.659746] el0_sync_compat_handler+0xa8/0xcc
[ 1279.659758] el0_sync_compat+0x188/0x1c0
[ 1279.659768] ---[ end trace cec200e5094155b4 ]---