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-rockchip/board.c b/arch/arm/mach-rockchip/board.c
index 8cd8911..628dc96 100644
--- a/arch/arm/mach-rockchip/board.c
+++ b/arch/arm/mach-rockchip/board.c
@@ -4,6 +4,7 @@
  */
 #include <common.h>
 #include <clk.h>
+#include <cpu_func.h>
 #include <dm.h>
 #include <ram.h>
 #include <syscon.h>