drm/radeon/kms: prefer high post dividers in legacy pll algo

the hw prefers higher post dividers

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_display.c b/drivers/gpu/drm/radeon/radeon_display.c
index 902f7ce..d276d6d 100644
--- a/drivers/gpu/drm/radeon/radeon_display.c
+++ b/drivers/gpu/drm/radeon/radeon_display.c
@@ -513,7 +513,7 @@
 		max_fractional_feed_div = pll->max_frac_feedback_div;
 	}
 
-	for (post_div = min_post_div; post_div <= max_post_div; ++post_div) {
+	for (post_div = max_post_div; post_div >= min_post_div; --post_div) {
 		uint32_t ref_div;
 
 		if ((pll->flags & RADEON_PLL_NO_ODD_POST_DIV) && (post_div & 1))