usb: kbd: fix typo

%s/a interrupt/an interrupt/

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/common/usb_kbd.c b/common/usb_kbd.c
index d178af2..8c09e61 100644
--- a/common/usb_kbd.c
+++ b/common/usb_kbd.c
@@ -339,7 +339,7 @@
 #if defined(CONFIG_SYS_USB_EVENT_POLL)
 	struct usb_kbd_pdata *data = dev->privptr;
 
-	/* Submit a interrupt transfer request */
+	/* Submit an interrupt transfer request */
 	if (usb_int_msg(dev, data->intpipe, &data->new[0],
 			data->intpktsize, data->intinterval, true) >= 0)
 		usb_kbd_irq_worker(dev);