drm/radeon/kms/avivo: add support for new pll selection algo

Supported on all AVIVO-based asics.
Can be disabled via the new_pll module parameter:
new_pll=0 - disable
new_pll=1 - enable
enabled by default

[airlied: fixed to use do_div]
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 5941e7d..c938bb5 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -88,6 +88,7 @@
 extern int radeon_testing;
 extern int radeon_connector_table;
 extern int radeon_tv;
+extern int radeon_new_pll;
 
 /*
  * Copy from radeon_drv.h so we don't have to include both and have conflicting