clk: divider: Fix clk_divider_round_rate() to use clk_readl()

commit 2cf9a578 upstream.

clk-divider uses clk_readl()/clk_writel() everywhere, except in
clk_divider_round_rate(), where plain readl() is used. Change this to
clk_readl(), as it makes a difference on powerpc.

Fixes: e6d5e7d9 ("clk-divider: Fix READ_ONLY when divider > 1")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

drivers/clk/clk-divider.c

@@ -263,7 +263,7 @@ static int clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 
 	/* if read only, just return current value */
 	if (divider->flags & CLK_DIVIDER_READ_ONLY) {
-		bestdiv = readl(divider->reg) >> divider->shift;
+		bestdiv = clk_readl(divider->reg) >> divider->shift;
 		bestdiv &= div_mask(divider);
 		bestdiv = _get_div(divider, bestdiv);
 		return bestdiv;