media: imx274: Fix error handling, add MAINTAINERS entry

Add the missing MAINTAINERS entry for imx274, fix error handling in driver
probe and unregister the correct control handler in driver remove.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>