V4L/DVB (12399): mt9v011: Add support for controlling frame rates

Implement g_parm/s_parm ioctls. Those are used to check the current
frame rate (in fps) and to set it to a value. In practice, there are
only 15 possible different speeds, due to chip limits.

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