drm/radeon: restructure cg/pg on cik (v2)

- use new cg/pg flags for finer grained clock and
powergating control
- restructure the cg/pg code so it can be called from
other components such as dpm

v2: fix build breakage from rebase

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
diff --git a/drivers/gpu/drm/radeon/cikd.h b/drivers/gpu/drm/radeon/cikd.h
index 259b81c..6a92f49 100644
--- a/drivers/gpu/drm/radeon/cikd.h
+++ b/drivers/gpu/drm/radeon/cikd.h
@@ -285,6 +285,7 @@
 
 #define PCIE_CNTL2                                        0x1001001c /* PCIE */
 #       define SLV_MEM_LS_EN                              (1 << 16)
+#       define SLV_MEM_AGGRESSIVE_LS_EN                   (1 << 17)
 #       define MST_MEM_LS_EN                              (1 << 18)
 #       define REPLAY_MEM_LS_EN                           (1 << 19)