cogland: Increase the display size to 800x600
cogland: Increase the display size to 800x600

The previous display size of 640x480 was a bit small to test with.

Reviewed-by: Robert Bragg <robert@linux.intel.com>

(cherry picked from commit 835626e220137765df5acf7419036218e3fc7c97)

Distrotech/cogl,Distrotech/cogl,Distrotech/cogl,Distrotech/cogl