drm/radeon/kms: evergreen/ni big endian fixes (v2)

Based on 6xx/7xx endian fixes from Cédric Cano.

v2: fix typo in shader

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/evergreend.h b/drivers/gpu/drm/radeon/evergreend.h
index afec1ac..eb4acf4 100644
--- a/drivers/gpu/drm/radeon/evergreend.h
+++ b/drivers/gpu/drm/radeon/evergreend.h
@@ -98,6 +98,7 @@
 #define		BUF_SWAP_32BIT					(2 << 16)
 #define	CP_RB_RPTR					0x8700
 #define	CP_RB_RPTR_ADDR					0xC10C
+#define		RB_RPTR_SWAP(x)					((x) << 0)
 #define	CP_RB_RPTR_ADDR_HI				0xC110
 #define	CP_RB_RPTR_WR					0xC108
 #define	CP_RB_WPTR					0xC114