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/drivers/mtd/nand/raw/sunxi_nand_spl.c b/drivers/mtd/nand/raw/sunxi_nand_spl.c
index 6cde981..8b2f7ea 100644
--- a/drivers/mtd/nand/raw/sunxi_nand_spl.c
+++ b/drivers/mtd/nand/raw/sunxi_nand_spl.c
@@ -10,6 +10,7 @@
 #include <config.h>
 #include <nand.h>
 #include <linux/ctype.h>
+#include <linux/delay.h>
 
 /* registers */
 #define NFC_CTL                    0x00000000