r300: Fix cliprect emit

This makes our handling of cliprects sane. drm_clip_rect always has exclusiv
bottom-right corners, but the hardware expects inclusive bottom-right corner
so we adjust this here.

This complements Michel Daenzer's commit 57aea290e1e0a26d1e74df6cff777eb9f03
to Mesa. See also http://bugs.freedesktop.org/show_bug.cgi?id=16123

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r300_cmdbuf.c b/drivers/gpu/drm/radeon/r300_cmdbuf.c
index b1fdfc6..4b27d9a 100644
--- a/drivers/gpu/drm/radeon/r300_cmdbuf.c
+++ b/drivers/gpu/drm/radeon/r300_cmdbuf.c
@@ -77,6 +77,9 @@
 				return -EFAULT;
 			}
 
+			box.x2--; /* Hardware expects inclusive bottom-right corner */
+			box.y2--;
+
 			if ((dev_priv->flags & RADEON_FAMILY_MASK) >= CHIP_RV515) {
 				box.x1 = (box.x1) &
 					R300_CLIPRECT_MASK;
@@ -95,8 +98,8 @@
 					R300_CLIPRECT_MASK;
 				box.y2 = (box.y2 + R300_CLIPRECT_OFFSET) &
 					R300_CLIPRECT_MASK;
-
 			}
+
 			OUT_RING((box.x1 << R300_CLIPRECT_X_SHIFT) |
 				 (box.y1 << R300_CLIPRECT_Y_SHIFT));
 			OUT_RING((box.x2 << R300_CLIPRECT_X_SHIFT) |