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/board/cobra5272/flash.c b/board/cobra5272/flash.c
index 9bf8248..ea3ed73 100644
--- a/board/cobra5272/flash.c
+++ b/board/cobra5272/flash.c
@@ -6,6 +6,7 @@
 
 #include <common.h>
 #include <console.h>
+#include <cpu_func.h>
 
 #define PHYS_FLASH_1 CONFIG_SYS_FLASH_BASE
 #define FLASH_BANK_SIZE 0x200000