usb: f_gsi: Set alt to 1 for rndis, rmnet and dpl unconditionally

Driver only sets alt to 1 if ep driver_data is NULL upon cable
connect for rndis, rmnet and dpl protocols. Since these protocols
only support single alt setting, there is no need to update alt
value based upon ep driver_data. It is possible for any protocol
to set driver_data upon connect and retain it upon disconnect. In
that case upon next connect data endpoints remain disabled.

Change-Id: I205b539be6625c9ca792d1731a4eeda5b48a2ccb
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>