[media] cx231xx: Added support for Carraera, Shelby, RDx_253S and VIDEO_GRABBER

Added support for new cx231xx boards - Carraera, Shelby, RDx_253S and
VIDEO_GRABBER.

[mchehab@redhat.com: Fix a merge conflict with BKL removal patches]
Signed-off-by: Palash Bandyopadhyay <palash.bandyopadhyay@conexant.com>
Signed-off-by: Devin Heitmueller <dheitmueller@hauppauge.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>