clk: optimize the divider walk in clk_divider_bestdiv()

Because _next_div() returns a valid divider, there is no need to
consult _is_valid_div() for the validity of the divider in every
iteration.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk-divider.c

@@ -303,9 +303,8 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 	 */
 	maxdiv = min(ULONG_MAX / rate, maxdiv);
 
-	for (i = 1; i <= maxdiv; i = _next_div(table, i, flags)) {
-		if (!_is_valid_div(table, i, flags))
-			continue;
+	for (i = _next_div(table, 0, flags); i <= maxdiv;
+					     i = _next_div(table, i, flags)) {
 		if (rate * i == parent_rate_saved) {
 			/*
 			 * It's the most ideal case if the requested rate can be