xf86-video-imxfb-vivante: Remove unused patches

xf86-video-imxfb-vivante: Remove unused patches

Following patches were not being used:

 - Makefile-fix-cross-compile.patch
 - Makefile.am-remove-prefixed-include-path.patch
 - build-Don-t-force-things-decided-by-build-system.patch

Those were included when working on 3.5.7-1.0.0-alpha release but not
removed, by mistake, when updating for 3.5.7-1.0.0-alpha.2 release.

Change-Id: Ib99562eaaa2d50845782f53a5b3ad3334cb9f48a
Reported-by: Evan Kotara <evan.kotara@freescale.com>
Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>