drm/radeon/si: restructure cg code (v3)

Resturcture clockgating code so that it can be
enabled/disabled from other components such as
dpm.

v2: make function static
v3: add fine grained cg controls

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/radeon_asic.c b/drivers/gpu/drm/radeon/radeon_asic.c
index dcdf5e0..3bd96cd 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.c
+++ b/drivers/gpu/drm/radeon/radeon_asic.c
@@ -2340,7 +2340,7 @@
 			rdev->cg_flags =
 				RADEON_CG_SUPPORT_GFX_MGCG |
 				RADEON_CG_SUPPORT_GFX_MGLS |
-				RADEON_CG_SUPPORT_GFX_CGCG |
+				/*RADEON_CG_SUPPORT_GFX_CGCG |*/
 				RADEON_CG_SUPPORT_GFX_CGLS |
 				RADEON_CG_SUPPORT_GFX_CGTS |
 				RADEON_CG_SUPPORT_GFX_CP_LS |
@@ -2357,7 +2357,7 @@
 			rdev->cg_flags =
 				RADEON_CG_SUPPORT_GFX_MGCG |
 				RADEON_CG_SUPPORT_GFX_MGLS |
-				RADEON_CG_SUPPORT_GFX_CGCG |
+				/*RADEON_CG_SUPPORT_GFX_CGCG |*/
 				RADEON_CG_SUPPORT_GFX_CGLS |
 				RADEON_CG_SUPPORT_GFX_CGTS |
 				RADEON_CG_SUPPORT_GFX_CP_LS |
@@ -2376,7 +2376,7 @@
 			rdev->cg_flags =
 				RADEON_CG_SUPPORT_GFX_MGCG |
 				RADEON_CG_SUPPORT_GFX_MGLS |
-				RADEON_CG_SUPPORT_GFX_CGCG |
+				/*RADEON_CG_SUPPORT_GFX_CGCG |*/
 				RADEON_CG_SUPPORT_GFX_CGLS |
 				RADEON_CG_SUPPORT_GFX_CGTS |
 				RADEON_CG_SUPPORT_GFX_CP_LS |
@@ -2397,7 +2397,7 @@
 			rdev->cg_flags =
 				RADEON_CG_SUPPORT_GFX_MGCG |
 				RADEON_CG_SUPPORT_GFX_MGLS |
-				RADEON_CG_SUPPORT_GFX_CGCG |
+				/*RADEON_CG_SUPPORT_GFX_CGCG |*/
 				RADEON_CG_SUPPORT_GFX_CGLS |
 				RADEON_CG_SUPPORT_GFX_CGTS |
 				RADEON_CG_SUPPORT_GFX_CP_LS |
@@ -2415,7 +2415,7 @@
 			rdev->cg_flags =
 				RADEON_CG_SUPPORT_GFX_MGCG |
 				RADEON_CG_SUPPORT_GFX_MGLS |
-				RADEON_CG_SUPPORT_GFX_CGCG |
+				/*RADEON_CG_SUPPORT_GFX_CGCG |*/
 				RADEON_CG_SUPPORT_GFX_CGLS |
 				RADEON_CG_SUPPORT_GFX_CGTS |
 				RADEON_CG_SUPPORT_GFX_CP_LS |