[media] saa7134: Get rid of struct saa7134_input.tv field

The saa7134_input.tv field was used to indicate if an input had
a RF signal for TV input. This is not needed anymore, as the input
type can be checked directly by the driver.

Also, due to a past bug when setting the TV standard at the
demod, all inputs should have this field set, with is wrong.

This reduces the size of the saa7134_boards by about 8KB,
on i386 (and probably twice on 64 bits), with is a nice
colateral effect:

   text	   data	    bss	    dec	    hex	filename
 241047	 136831	  66356	 444234	  6c74a	drivers/media/pci/saa7134/saa7134.o.old
 240851  128895   66292  436038   6a746 drivers/media/pci/saa7134/saa7134.o

Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>