media: mmp-camera.h: add missing platform data

Those definitions used to be part of the original patch:
	https://patchwork.kernel.org/patch/2815221/

But, somehow, nobody ever noticed until today. Years later,
Arnd discovered that mmp-camera driver doesn't build and make
it depend on BROKEN.

Add the missing bits here, in order to remove BROKEN dependency.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>