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/cmd/ti/ddr3.c b/cmd/ti/ddr3.c
index 448a7f5..5513089 100644
--- a/cmd/ti/ddr3.c
+++ b/cmd/ti/ddr3.c
@@ -5,6 +5,7 @@
  * Copyright (C) 2012-2017 Texas Instruments Incorporated, <www.ti.com>
  */
 
+#include <cpu_func.h>
 #include <asm/arch/hardware.h>
 #include <asm/cache.h>
 #include <asm/emif.h>