clk: stm32f4: Convert to clk_hw based provider APIs

We're removing struct clk from the clk provider API, so switch
this code to using the clk_hw based provider APIs.

Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
diff --git a/drivers/clk/clk-stm32f4.c b/drivers/clk/clk-stm32f4.c
index 5cfe507..fd89e77 100644
--- a/drivers/clk/clk-stm32f4.c
+++ b/drivers/clk/clk-stm32f4.c
@@ -178,8 +178,7 @@
 	if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
 		unsigned long best_parent = rate / mult;
 
-		*prate =
-		    __clk_round_rate(__clk_get_parent(hw->clk), best_parent);
+		*prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);
 	}
 
 	return *prate * mult;