usb: chipidea: host: more enhancement when ci->hcd is NULL

Like http://marc.info/?l=linux-usb&m=138200449428874&w=2 said:
two more things are needed to be done:

- If host_start fails, the host_stop should not be called, so we
add check that ci->hcd is not NULL.
- if the host_start fails at the beginning, we need to consider
regulator mismatch issue.
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/chipidea/host.c

@@ -103,15 +103,15 @@ static void host_stop(struct ci_hdrc *ci)
 	if (hcd) {
 		usb_remove_hcd(hcd);
 		usb_put_hcd(hcd);
-	}
 		if (ci->platdata->reg_vbus)
 			regulator_disable(ci->platdata->reg_vbus);
+	}
 }
 
 
 void ci_hdrc_host_destroy(struct ci_hdrc *ci)
 {
-	if (ci->role == CI_ROLE_HOST)
+	if (ci->role == CI_ROLE_HOST && ci->hcd)
 		host_stop(ci);
 }