Commit 
40ed51a4b (usb: chipidea: host: add vbus regulator
control) introduced a smatch complaint because regulator_disable() is called
without checking whether ci->platdata->reg_vbus is not NULL.
Fix this by adding the check.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
 
        return ret;
 
 disable_reg:
-       regulator_disable(ci->platdata->reg_vbus);
+       if (ci->platdata->reg_vbus)
+               regulator_disable(ci->platdata->reg_vbus);
 
 put_hcd:
        usb_put_hcd(hcd);