bnxt_en: Failure to update PHY is not fatal condition.

If we fail to update the PHY, we should print a warning and continue.
The current code to exit is buggy as it has not freed up the NIC
resources yet.

Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>