Lower the minimum height to 360 to be consistent with the webcam input of vivid.

The 480 was rather arbitrary but it made it harder to use vivid as a source for
encoding since the default resolution when you load vivid is 640x360.
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>