media: videodev2.h: Add new DV flag CAN_DETECT_REDUCED_FPS

Add a new flag to UAPI for DV timings which, whenever set,
indicates that hardware can detect the difference between
regular FPS and 1000/1001 FPS.

This is specific to HDMI receivers. Also, it is only valid
when V4L2_DV_FL_CAN_REDUCE_FPS is set.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>