V4L/DVB: V4L2: sh_vou: VOU does support the full PAL resolution too

SH7724 datasheet specifies 480 pixels as the VOU maximum vertical resolution.
This is a bug in the datasheet, VOU also supports the full PAL resolution: 576
lines. Adjust the driver accordingly.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>