clk: pxa clocks build system fix

Fix the building of pxa clock drivers so that the files are actually
compiled if and only if COMMON_CLK was selected by the architecture.

This prevents conflicts with mach-pxa clock legacy implementation.
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/Kconfig

@@ -120,6 +120,11 @@ config COMMON_CLK_PALMAS
 	  This driver supports TI Palmas devices 32KHz output KG and KG_AUDIO
 	  using common clock framework.
 
+config COMMON_CLK_PXA
+	def_bool COMMON_CLK && ARCH_PXA
+	---help---
+	  Sypport for the Marvell PXA SoC.
+
 source "drivers/clk/qcom/Kconfig"
 
 endmenu

drivers/clk/Makefile

@@ -51,7 +51,7 @@ obj-$(CONFIG_ARCH_MMP)			+= mmp/
 endif
 obj-$(CONFIG_PLAT_ORION)		+= mvebu/
 obj-$(CONFIG_ARCH_MXS)			+= mxs/
-obj-$(CONFIG_ARCH_PXA)			+= pxa/
+obj-$(CONFIG_COMMON_CLK_PXA)		+= pxa/
 obj-$(CONFIG_COMMON_CLK_QCOM)		+= qcom/
 obj-$(CONFIG_ARCH_ROCKCHIP)		+= rockchip/
 obj-$(CONFIG_COMMON_CLK_SAMSUNG)	+= samsung/