drm/radeon: improve GPU lockup debugging info on r6xx/r7xx/r8xx/r9xx

Print various CP register that have valuable informations regarding
GPU lockup.

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/nid.h b/drivers/gpu/drm/radeon/nid.h
index a0b9806..870db34 100644
--- a/drivers/gpu/drm/radeon/nid.h
+++ b/drivers/gpu/drm/radeon/nid.h
@@ -236,6 +236,10 @@
 #define	CP_SEM_WAIT_TIMER				0x85BC
 #define	CP_SEM_INCOMPLETE_TIMER_CNTL			0x85C8
 #define	CP_COHER_CNTL2					0x85E8
+#define	CP_STALLED_STAT1			0x8674
+#define	CP_STALLED_STAT2			0x8678
+#define	CP_BUSY_STAT				0x867C
+#define	CP_STAT						0x8680
 #define CP_ME_CNTL					0x86D8
 #define		CP_ME_HALT					(1 << 28)
 #define		CP_PFP_HALT					(1 << 26)