ARM: at91: clock: add a new file to handle clock

To reduce the duplicated code, add a new file to accommodate
the peripheral's and system's clock handle code, shared with
the SoCs with different ARM core.

Signed-off-by: Wenyou Yang <wenyou.yang@atmel.com>
Tested-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Andreas Bießmann <andreas.devel@googlemail.com>
diff --git a/arch/arm/mach-at91/Makefile b/arch/arm/mach-at91/Makefile
index abd1d13..4424523 100644
--- a/arch/arm/mach-at91/Makefile
+++ b/arch/arm/mach-at91/Makefile
@@ -15,6 +15,7 @@
 obj-y += spl.o
 endif
 
+obj-y += clock.o
 obj-$(CONFIG_CPU_ARM920T)	+= arm920t/
 obj-$(CONFIG_CPU_ARM926EJS)	+= arm926ejs/
 obj-$(CONFIG_CPU_V7)		+= armv7/