drm/radeon/kms: update new pll algo

- add support for pre-avivo chips
- add support for fixed post/ref dividers
- add support for non-fractional fb dividers

By default avivo chips use the new algo and
pre-avivo chips use the old algo. Use the "new_pll"
module option to toggle between them.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 8912f2e8..1702b82 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -133,7 +133,7 @@
 /* pll algo */
 enum radeon_pll_algo {
 	PLL_ALGO_LEGACY,
-	PLL_ALGO_AVIVO
+	PLL_ALGO_NEW
 };
 
 struct radeon_pll {