usb:ci_udc: don't overwrite configuration on pullup

change writel to writebits32 in ci_pullup() in order
to keep phy configuration in tact.

Signed-off-by: Ramon Fried <ramon.fried@gmail.com>
diff --git a/drivers/usb/gadget/ci_udc.c b/drivers/usb/gadget/ci_udc.c
index 8d23fab..0a84f68 100644
--- a/drivers/usb/gadget/ci_udc.c
+++ b/drivers/usb/gadget/ci_udc.c
@@ -906,7 +906,8 @@
 		writel(0xffffffff, &udc->epflush);
 
 		/* Turn on the USB connection by enabling the pullup resistor */
-		writel(USBCMD_ITC(MICRO_8FRAME) | USBCMD_RUN, &udc->usbcmd);
+		setbits_le32(&udc->usbcmd, USBCMD_ITC(MICRO_8FRAME) |
+			     USBCMD_RUN);
 	} else {
 		udc_disconnect();
 	}