common: Move some cache and MMU functions out of common.h

These functions belong in cpu_func.h. Another option would be cache.h
but that code uses driver model and we have not moved these cache
functions to use driver model. Since they are CPU-related it seems
reasonable to put them here.

Move them over.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/arch/arm/mach-s5pc1xx/cache.c b/arch/arm/mach-s5pc1xx/cache.c
index 0b879b5..7816ba1 100644
--- a/arch/arm/mach-s5pc1xx/cache.c
+++ b/arch/arm/mach-s5pc1xx/cache.c
@@ -8,6 +8,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 
 #if !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)
 void enable_caches(void)