drm/radeon/kms/pm: add additional asic callbacks

- pm_misc() - handles voltage, pcie lanes, and other non
clock related power mode settings.  Currently disabled.
Needs further debugging

- pm_prepare() - disables crtc mem requests right now.
All memory clients need to be disabled when changing
memory clocks.  This function can be expanded to include
disabling fb access as well.

- pm_finish() - enable active memory clients.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index 4f7f318..38f75f5 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -304,6 +304,11 @@
 		DRM_INFO("GUI not idle!!!\n");
 }
 
+void r600_pm_misc(struct radeon_device *rdev)
+{
+
+}
+
 bool r600_gui_idle(struct radeon_device *rdev)
 {
 	if (RREG32(GRBM_STATUS) & GUI_ACTIVE)