media: vimc: Fix wrong function called when vimc_init() fails

media: vimc: Fix wrong function called when vimc_init() fails

In vimc_init(), when platform_driver_register(&vimc_pdrv) fails,
platform_driver_unregister(&vimc_pdrv) is wrongly called rather than
platform_device_unregister(&vimc_pdev), which causes kernel warning:

 Unexpected driver unregister!
 WARNING: CPU: 1 PID: 14517 at drivers/base/driver.c:270 driver_unregister+0x8f/0xb0
 RIP: 0010:driver_unregister+0x8f/0xb0
 Call Trace:
  <TASK>
  vimc_init+0x7d/0x1000 [vimc]
  do_one_initcall+0xd0/0x4e0
  do_init_module+0x1cf/0x6b0
  load_module+0x65c2/0x7820

Fixes: 4a29b7090749 ("[media] vimc: Subdevices as modules")
Signed-off-by: Chen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>