media: staging: atomisp: Remove IMX sensor support

This sensor is not used by any known ACPI-enabled platform
(and no kernel users for it so far).

Just remove it for good until we get a platform which actually uses it.

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