V4L/DVB (11688): gspca - m5602-s5k4aa: Fixup SXGA resolution.

The SXGA resolution doesn't work unless you first force the VGA resolution.
More investigation is needed in order to fix this the "right" way.

Signed-off-by: Grégory Lardière <spmf2004-m560x@yahoo.fr>
Signed-off-by: Erik Andrén <erik.andren@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>