media: smiapp: Move definitions under driver directory

include/media/i2c/smiapp.h was meant to serve systems where the sensor is
enumerated through platform data. That's no longer necessary, hopefully
not even in out-of-tree use cases. Move the definitions to the appropriate
headers.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>