rt2800usb: initialize H2M_INT_SRC register

Ralink USB driver initialize H2M_INT_SRC to 0 after firmware load, and
never touch this register later. It is not touched at all by Ralink PCI
driver.

Acked-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
index 22a1a8f..3e194b7 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -448,6 +448,8 @@
 	 */
 	rt2800_register_write(rt2x00dev, H2M_BBP_AGENT, 0);
 	rt2800_register_write(rt2x00dev, H2M_MAILBOX_CSR, 0);
+	if (rt2x00_is_usb(rt2x00dev))
+		rt2800_register_write(rt2x00dev, H2M_INT_SRC, 0);
 	msleep(1);
 
 	return 0;