tg3: Clean tg3_init_one()

Tg3's firmware is no longer loaded from tg3_init_one().  Remove the
error path that releases the firmware back to the system.

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>