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/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 6be40d0..b7289ba 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -31,6 +31,7 @@
 #include <asm/byteorder.h>
 #include <asm/unaligned.h>
 #include <env_internal.h>
+#include <linux/delay.h>
 #include <mtd/cfi_flash.h>
 #include <watchdog.h>