Fix the following coccicheck warning:

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:1991:5-46: WARNING:
Comparison to bool
drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:1993:10-54: WARNING:
Comparison to bool
drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:2380:5-38: WARNING:
Comparison to bool
Signed-off-by: NJason Yan <yanaijie@huawei.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>