[media] media: Remove pre-allocated entity enumeration bitmap

The bitmaps for entity enumerations used to be statically allocated. Now
that the drivers have been converted to use the new interface which
explicitly initialises the enum objects, drop the pre-allocated bitmaps.

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