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/usb/host/ehci-rmobile.c b/drivers/usb/host/ehci-rmobile.c
index 4868581..130b73d 100644
--- a/drivers/usb/host/ehci-rmobile.c
+++ b/drivers/usb/host/ehci-rmobile.c
@@ -9,6 +9,7 @@
 #include <common.h>
 #include <asm/io.h>
 #include <asm/arch/ehci-rmobile.h>
+#include <linux/delay.h>
 #include "ehci.h"
 
 #if defined(CONFIG_R8A7740)