media: v4l2-device.h: document helper macros

There are several macros that aren't documented using kernel-docs
markups.

Document them.

While here, add cross-references to structs on this file.

Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
This commit is contained in:
Mauro Carvalho Chehab 2017-09-22 12:31:02 -04:00
commit d651ff916e