media: max9286: Fix memleak in max9286_v4l2_register()

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

media: max9286: Fix memleak in max9286_v4l2_register()

There is a kmemleak when testing the media/i2c/max9286.c with bpf mock
device:

kmemleak: 5 new suspected memory leaks (see /sys/kernel/debug/kmemleak)

unreferenced object 0xffff88810defc400 (size 256):
comm "python3", pid 278, jiffies 4294737563 (age 31.978s)
hex dump (first 32 bytes):
28 06 a7 0a 81 88 ff ff 00 fe 22 12 81 88 ff ff (.........".....
10 c4 ef 0d 81 88 ff ff 10 c4 ef 0d 81 88 ff ff ................
backtrace:
[<00000000191de6a7>] __kmalloc_node+0x44/0x1b0
[<000000002f4912b7>] kvmalloc_node+0x34/0x180
[<0000000057dc4cae>] v4l2_ctrl_new+0x325/0x10f0 [videodev]
[<0000000026030272>] v4l2_ctrl_new_std+0x16f/0x210 [videodev]
[<00000000f0d9ea2f>] max9286_probe+0x76e/0xbff [max9286]
[<00000000ea8f6455>] i2c_device_probe+0x28d/0x680
[<0000000087529af3>] really_probe+0x17c/0x3f0
[<00000000b08be526>] __driver_probe_device+0xe3/0x170
[<000000004382edea>] driver_probe_device+0x49/0x120
[<000000007bde528a>] __device_attach_driver+0xf7/0x150
[<000000009f9c6ab4>] bus_for_each_drv+0x114/0x180
[<00000000c8aaf588>] __device_attach+0x1e5/0x2d0
[<0000000041cc06b9>] bus_probe_device+0x126/0x140
[<000000002309860d>] device_add+0x810/0x1130
[<000000002827bf98>] i2c_new_client_device+0x359/0x4f0
[<00000000593bdc85>] of_i2c_register_device+0xf1/0x110

max9286_v4l2_register() calls v4l2_ctrl_new_std(), but won't free the
created v412_ctrl when fwnode_graph_get_endpoint_by_id() failed, which
causes the memleak. Call v4l2_ctrl_handler_free() to free the v412_ctrl.