USB: at91_udc: include linux/prefetch.h explicitly

Signed-off-by: NJean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Patrice Vilchez <patrice.vilchez@atmel.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/at91_udc.c

@@ -35,6 +35,7 @@
 #include <linux/list.h>
 #include <linux/interrupt.h>
 #include <linux/proc_fs.h>
+#include <linux/prefetch.h>
 #include <linux/clk.h>
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>