usb: gadget: don't change ep name for dwc3 while ep autoconfig

As the SDP protocol use the predefined ep num for communication, we can't
change its name hence reset its ep num while do ep autoconfig, this is
only apply for SPL.

Signed-off-by: Li Jun <jun.li@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>