[media] pwc: Remove software emulation of arbritary resolutions

The pwc driver claims to support any resolution between 160x120
and 640x480, but emulates this by simply drawing a black border
around the image. Userspace can draw its own black border if it
really wants one.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>