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/arch/powerpc/lib/bootm.c b/arch/powerpc/lib/bootm.c
index 84691b7..f2e670e 100644
--- a/arch/powerpc/lib/bootm.c
+++ b/arch/powerpc/lib/bootm.c
@@ -8,6 +8,7 @@
 
 
 #include <common.h>
+#include <cpu_func.h>
 #include <env.h>
 #include <watchdog.h>
 #include <command.h>