[media] cx23885: Control cleanup on the MPEG Encoder

Added three new control calls (g_std, querystd and g_ctrl) to
the -417 driver. Also routed other controls through the main
cx23885 driver meaning that the controls for the 417 and the
raw video device all enter the driver code and are handled
in a single place.

Signed-off-by: Steven Toth <stoth@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>