media: ov2640: set all mbus format field when G_FMT and S_FMT ioctls

This driver doesn't set all members of mbus format field when the
VIDIOC_SUBDEV_{S,G}_FMT ioctls are called.

This is detected by v4l2-compliance.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>