xf86-video-geode: Upgrade to 2.11.15

The latest driver corrected a number of issues and compiles without
warnings with just one patch.  The header included by the given patch
is already included in the geode master line, so will not be be
required after the next geode version release.

Signed-off-by: Brian Lloyd <blloyd@familyhonor.net>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>