V4L/DVB (12617): gspca_pac207: enable higher framerates / lower exposure settings

Now that we've figured out the higher compression settings (supported in
libv4l-0.6.0 and later, so after this patch the driver should be used with
libv4l-0.6.0 or higher only!), we can enable higher framerates. Which
means lower exposure times, which is important for the use of the pac207
in full daylight.

This patch also tweakes the brightness default and the per color gain
balances to use the values which are adviced by Pixart in the pac207
application note.

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