drm/radeon/kms: block depthxy offset from use from userspace.

This could be used to bypass CS checks.

Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/reg_srcs/r300

@@ -725,4 +725,3 @@ r300 0x4f60
 0x4F50 ZB_HIZ_RDINDEX
 0x4F54 ZB_HIZ_PITCH
 0x4F58 ZB_ZPASS_DATA
-0x4F60 ZB_DEPTHXY_OFFSET

drivers/gpu/drm/radeon/reg_srcs/rs600

@@ -725,4 +725,3 @@ rs600 0x6d40
 0x4F50 ZB_HIZ_RDINDEX
 0x4F54 ZB_HIZ_PITCH
 0x4F58 ZB_ZPASS_DATA
-0x4F60 ZB_DEPTHXY_OFFSET

drivers/gpu/drm/radeon/reg_srcs/rv515

@@ -483,4 +483,3 @@ rv515 0x6d40
 0x4F50 ZB_HIZ_RDINDEX
 0x4F54 ZB_HIZ_PITCH
 0x4F58 ZB_ZPASS_DATA
-0x4F60 ZB_DEPTHXY_OFFSET