arm: mmp: move pxa910 clock definition to separated file

move pxa910 clock definition to another file. Then pxa910 can
choose common clock framework or private clock framework.

Signed-off-by: Chao Xie <xiechao.mail@gmail.com>
Signed-off-by: Haojian Zhuang <haojian.zhuang@gmail.com>
diff --git a/arch/arm/mach-mmp/common.h b/arch/arm/mach-mmp/common.h
index e47f73f..1cad41b 100644
--- a/arch/arm/mach-mmp/common.h
+++ b/arch/arm/mach-mmp/common.h
@@ -8,3 +8,4 @@
 extern void __init mmp_map_io(void);
 extern void mmp_restart(char, const char *);
 extern void __init pxa168_clk_init(void);
+extern void __init pxa910_clk_init(void);