msm: Disallow mapping buffers with modifiers

GBM users don't know how to do CPU access to any buffer with a modfier.
So they have no business mapping them.

This fixes "jailbar" corruption resulting from something somewhere
trying to do sw rendering to a UBWC buffer

BUG=b:237708681
TEST=Alt-TopRowFullScreenButton on herobrine

Change-Id: Ideb80df17d4f174600b7f605f563f275655a88da
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/minigbm/+/4195657
Tested-by: Rob Clark <robdclark@chromium.org>
Commit-Queue: Yiwei Zhang <zzyiwei@chromium.org>
Commit-Queue: Rob Clark <robdclark@chromium.org>
Auto-Submit: Rob Clark <robdclark@chromium.org>
Reviewed-by: Yiwei Zhang <zzyiwei@chromium.org>
diff --git a/msm.c b/msm.c
index e696686..f6e8247 100644
--- a/msm.c
+++ b/msm.c
@@ -355,6 +355,9 @@
 	int ret;
 	struct drm_msm_gem_info req = { 0 };
 
+	if (bo->meta.format_modifier)
+		return MAP_FAILED;
+
 	req.handle = bo->handles[0].u32;
 	ret = drmIoctl(bo->drv->fd, DRM_IOCTL_MSM_GEM_INFO, &req);
 	if (ret) {