V4L/DVB (11647): gspca - m5602-po1030: Disable QVGA for now

Getting QVGA to be supported on the po1030 seems harder than I first thought. I need access to the proper hardware in order to fix it up.

Signed-off-by: Erik Andrén <erik.andren@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>