drm/radeon/kms: Convert RV515 to new init path and associated cleanup

Convert the rv515 asic support to new init path also add an explanation
in radeon.h about the new init path. There is also few cleanups
associated with this change (others asic calling rv515 helper
functions).

Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>

drivers/gpu/drm/radeon/rs690.c

@@ -40,7 +40,6 @@ void rs400_gart_disable(struct radeon_device *rdev);
 int rs400_gart_enable(struct radeon_device *rdev);
 void rs400_gart_adjust_size(struct radeon_device *rdev);
 void rs600_mc_disable_clients(struct radeon_device *rdev);
-void rs600_disable_vga(struct radeon_device *rdev);
 
 /* This files gather functions specifics to :
  * rs690,rs740
@@ -125,7 +124,7 @@ void rs690_gpu_init(struct radeon_device *rdev)
 {
 	/* FIXME: HDP same place on rs690 ? */
 	r100_hdp_reset(rdev);
-	rs600_disable_vga(rdev);
+	rv515_vga_render_disable(rdev);
 	/* FIXME: is this correct ? */
 	r420_pipes_init(rdev);
 	if (rs690_mc_wait_for_idle(rdev)) {