usb: chipidea: fix id change handling

Re-enable chipidea irq even if there's no role changing to do. This is
a problem since b183c19f ("USB: chipidea: re-order irq handling to avoid
unhandled irqs"); when it manifests, chipidea irq gets disabled for good.

Cc: stable@vger.kernel.org # v3.7
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/core.c

@@ -276,8 +276,9 @@ static void ci_role_work(struct work_struct *work)
 
 		ci_role_stop(ci);
 		ci_role_start(ci, role);
-		enable_irq(ci->irq);
 	}
+
+	enable_irq(ci->irq);
 }
 
 static irqreturn_t ci_irq(int irq, void *data)