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/board/socrates/socrates.c b/board/socrates/socrates.c
index c51f3e4..58c5f75 100644
--- a/board/socrates/socrates.c
+++ b/board/socrates/socrates.c
@@ -20,6 +20,7 @@
 #include <asm/immap_85xx.h>
 #include <ioports.h>
 #include <flash.h>
+#include <linux/delay.h>
 #include <linux/libfdt.h>
 #include <fdt_support.h>
 #include <asm/io.h>