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/serial/serial-uclass.c b/drivers/serial/serial-uclass.c
index 7703c67..a0af0e6 100644
--- a/drivers/serial/serial-uclass.c
+++ b/drivers/serial/serial-uclass.c
@@ -15,6 +15,7 @@
 #include <dm/lists.h>
 #include <dm/device-internal.h>
 #include <dm/of_access.h>
+#include <linux/delay.h>
 
 DECLARE_GLOBAL_DATA_PTR;