net: usbnet: Undo double reservation

This reserves twice if we're not in raw IP mode. Drop it.

Change-Id: I7d4ce53c938e809e4e63d08188cb2e9d03f93dfa
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Francisco Franco <franciscofranco.1990@gmail.com>