usb: chipidea: need to mask when writting endptflush and endptprime

ENDPTFLUSH and ENDPTPRIME registers are set by software and clear
by hardware. There is a bit for each endpoint. When we are setting
a bit for an endpoint we should make sure we do not touch other
endpoint bit. There is a race condition if the hardware clear the
bit between the read and the write in hw_write.

Cc: stable <[e-mail]> # 3.11+
Signed-off-by: Peter Chen <[e-mail]>
Signed-off-by: Matthieu CASTET <[e-mail]>
Tested-by: Michael Grzeschik <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/chipidea/udc.c

···
 
 	do {
 		/* flush any pending transfer */
-		hw_write(ci, OP_ENDPTFLUSH, BIT(n), BIT(n));
+		hw_write(ci, OP_ENDPTFLUSH, ~0, BIT(n));
 		while (hw_read(ci, OP_ENDPTFLUSH, BIT(n)))
 			cpu_relax();
 	} while (hw_read(ci, OP_ENDPTSTAT, BIT(n)));
···
 	if (is_ctrl && dir == RX && hw_read(ci, OP_ENDPTSETUPSTAT, BIT(num)))
 		return -EAGAIN;
 
-	hw_write(ci, OP_ENDPTPRIME, BIT(n), BIT(n));
+	hw_write(ci, OP_ENDPTPRIME, ~0, BIT(n));
 
 	while (hw_read(ci, OP_ENDPTPRIME, BIT(n)))
 		cpu_relax();