[ARM] pxa: move pwm.c to common plat-pxa directory

Signed-off-by: Eric Miao <eric.miao@marvell.com>
diff --git a/arch/arm/plat-pxa/Makefile b/arch/arm/plat-pxa/Makefile
index 8f2c4c7..0264bfb 100644
--- a/arch/arm/plat-pxa/Makefile
+++ b/arch/arm/plat-pxa/Makefile
@@ -7,3 +7,5 @@
 obj-$(CONFIG_GENERIC_GPIO)	+= gpio.o
 obj-$(CONFIG_PXA3xx)		+= mfp.o
 obj-$(CONFIG_ARCH_MMP)		+= mfp.o
+
+obj-$(CONFIG_HAVE_PWM)		+= pwm.o