ARM: mxs: convert platform code to clk_prepare/clk_unprepare

The patch converts mxs platform code to clk_prepare/clk_unprepare
by using helper functions clk_prepare_enable/clk_disable_unprepare.

Signed-off-by: Richard Zhao <richard.zhao@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-mxs/clock-mx23.c b/arch/arm/mach-mxs/clock-mx23.c
index 0163b6d..e12e112 100644
--- a/arch/arm/mach-mxs/clock-mx23.c
+++ b/arch/arm/mach-mxs/clock-mx23.c
@@ -545,11 +545,11 @@
 	 */
 	clk_set_parent(&ssp_clk, &ref_io_clk);
 
-	clk_enable(&cpu_clk);
-	clk_enable(&hbus_clk);
-	clk_enable(&xbus_clk);
-	clk_enable(&emi_clk);
-	clk_enable(&uart_clk);
+	clk_prepare_enable(&cpu_clk);
+	clk_prepare_enable(&hbus_clk);
+	clk_prepare_enable(&xbus_clk);
+	clk_prepare_enable(&emi_clk);
+	clk_prepare_enable(&uart_clk);
 
 	clkdev_add_table(lookups, ARRAY_SIZE(lookups));