Revert "drm/gma500: Use drm_aperture_remove_conflicting_pci_framebuffers"

This reverts commit cccfcbb9 which is
commit 80e99398 upstream.

It breaks the Android ABI and can be brought back later in an abi-safe
way if needed.

Bug: 161946584
Change-Id: I98437f0d8222293d93ad48311e8b719931f68c75
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>