gma500: enable GEM mmap

Support mapping of GEM objects. This ought to be a small plumbing change but instead we have to cut and paste a pile of stuff into the driver. This really wants to be handled *IN* GEM

You can now allocate, mmap and munmap GEM objects in the driver. You can't yet map them into the GART or display them however.

---

 drivers/staging/gma500/psb_drv.c |    4 +-
 drivers/staging/gma500/psb_gem.c |   86 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 84 insertions(+), 6 deletions(-)

index 360d582..4da0b18 100644
@@ -1422,11 +1422,11 @@ static struct drm_driver driver = {
 		 .open = drm_open,
 		 .release = drm_release,
 		 .unlocked_ioctl = psb_unlocked_ioctl,
-		 .mmap = drm_mmap,
+		 .mmap = drm_gem_mmap,
 		 .poll = drm_poll,
 		 .fasync = drm_fasync,
 		 .read = drm_read,
-		 },
+	 },
 	.name = DRIVER_NAME,
 	.desc = DRIVER_DESC,
 	.date = PSB_DRM_DRIVER_DATE,