ARM: mxs: switch to common clk framework

It switches mxs clock support to common clk framework based drivers.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 36586dba..2095a51 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -468,6 +468,7 @@
 	select ARCH_REQUIRE_GPIOLIB
 	select CLKDEV_LOOKUP
 	select CLKSRC_MMIO
+	select COMMON_CLK
 	select HAVE_CLK_PREPARE
 	help
 	  Support for Freescale MXS-based family of processors