arm: mmp: make private clock definition exclude from common clock

the clock.c is mmp private implementation, make it excluded
from common clock framework
Signed-off-by: Chao Xie <xiechao.mail@gmail.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>

arch/arm/mach-mmp/Makefile

@@ -2,13 +2,16 @@
 # Makefile for Marvell's PXA168 processors line
 #
 
-obj-y				+= common.o clock.o devices.o time.o irq.o
+obj-y				+= common.o devices.o time.o irq.o
 
 # SoC support
 obj-$(CONFIG_CPU_PXA168)	+= pxa168.o
 obj-$(CONFIG_CPU_PXA910)	+= pxa910.o
 obj-$(CONFIG_CPU_MMP2)		+= mmp2.o sram.o
 
+ifeq ($(CONFIG_COMMON_CLK), )
+obj-y				+= clock.o
+endif
 ifeq ($(CONFIG_PM),y)
 obj-$(CONFIG_CPU_PXA910)	+= pm-pxa910.o
 obj-$(CONFIG_CPU_MMP2)		+= pm-mmp2.o