common: Move ARM cache operations out of common.h

These functions are CPU-related and do not use driver model. Move them to
cpu_func.h

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

cmd/disk.c

@@ -5,6 +5,7 @@
  */
 #include <common.h>
 #include <command.h>
+#include <cpu_func.h>
 #include <part.h>
 
 int common_diskboot(cmd_tbl_t *cmdtp, const char *intf, int argc,