[media] saa7115: allow input standard autodetection for more chips

Autodetect input's standard using field frequency detection
feature (FIDT in status byte at 0x1F) of the chips saa7111/
saa7111a/saa7113/saa7114/saa7118.

Signed-off-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>