common: Drop linux/delay.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/cmd/bootmenu.c b/cmd/bootmenu.c
index 551420d..18efe25 100644
--- a/cmd/bootmenu.c
+++ b/cmd/bootmenu.c
@@ -11,6 +11,7 @@
 #include <menu.h>
 #include <watchdog.h>
 #include <malloc.h>
+#include <linux/delay.h>
 #include <linux/string.h>
 
 /* maximum bootmenu entries */