Move ALLOC_CACHE_ALIGN_BUFFER() to the new memalign.h header

Now that we have a new header file for cache-aligned allocation, we should
move the stack-based allocation macro there also.

Signed-off-by: Simon Glass <sjg@chromium.org>

common/usb_kbd.c

@@ -11,6 +11,7 @@
 #include <dm.h>
 #include <errno.h>
 #include <malloc.h>
+#include <memalign.h>
 #include <stdio_dev.h>
 #include <asm/byteorder.h>