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>
diff --git a/drivers/spi/mxs_spi.c b/drivers/spi/mxs_spi.c
index 58b1c67..3ca3088 100644
--- a/drivers/spi/mxs_spi.c
+++ b/drivers/spi/mxs_spi.c
@@ -13,6 +13,7 @@
  */
 
 #include <common.h>
+#include <cpu_func.h>
 #include <malloc.h>
 #include <memalign.h>
 #include <spi.h>