media: vsp1: Fix YCbCr planar formats pitch calculation

YCbCr planar formats can have different pitch values for the luma and
chroma planes. This isn't taken into account in the driver. Fix it.

Based on a BSP patch from Koji Matsuoka <koji.matsuoka.xm@renesas.com>.

Fixes: 7863ac50 ("drm: rcar-du: Add tri-planar memory formats support")
[Updated documentation of the struct vsp1_du_atomic_config pitch field]

Signed-off-by: Koji Matsuoka <koji.matsuoka.xm@renesas.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>