drm/radeon: add basic zmask/hiz support (v4)

This interface allows userspace to request hyperz support, it probably
needs more locking, and really reporting that you can have hyperz is racy
since someone else might get it before you do.

v2: modify so we pass 0 valued packets to let DDX/r300c keep working.
also fixed incorrect 0x4f1c reference.

v3: fixup zb_bw_cntl so older drivers keep working

v4: add locking, fixup SC_HYPERZ_EN - patch stream to disable hiz

Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/include/drm/radeon_drm.h b/include/drm/radeon_drm.h
index ac5f040..0acaf8f 100644
--- a/include/drm/radeon_drm.h
+++ b/include/drm/radeon_drm.h
@@ -905,6 +905,7 @@
 #define RADEON_INFO_CRTC_FROM_ID	0x04
 #define RADEON_INFO_ACCEL_WORKING2	0x05
 #define RADEON_INFO_TILING_CONFIG	0x06
+#define RADEON_INFO_WANT_HYPERZ		0x07
 
 struct drm_radeon_info {
 	uint32_t		request;