common: Move clock functions into a new file

These three clock functions don't use driver model and should be migrated.
In the meantime, create a new file to hold them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/powerpc/cpu/mpc85xx/speed.c b/arch/powerpc/cpu/mpc85xx/speed.c
index 0c5252e..773ae08 100644
--- a/arch/powerpc/cpu/mpc85xx/speed.c
+++ b/arch/powerpc/cpu/mpc85xx/speed.c
@@ -574,8 +574,7 @@
 #endif
 }
 
-
-int get_clocks (void)
+int get_clocks(void)
 {
 	sys_info_t sys_info;
 #ifdef CONFIG_ARCH_MPC8544
@@ -653,7 +652,7 @@
  * get_bus_freq
  * return system bus freq in Hz
  *********************************************/
-ulong get_bus_freq (ulong dummy)
+ulong get_bus_freq(ulong dummy)
 {
 	return gd->bus_clk;
 }