Add a header file for the tvp5150 input connectors constants that
can be shared between the driver and Device Tree source files.

[mchehab@osg.samsung.com: rename tvp5150.h also at em28xx-cards.c]
Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>