bnxt_en: do not call napi_hash_add()

This is automatically done from netif_napi_add(), and we want to not
export napi_hash_add() anymore in the following patch.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Michael Chan <michael.chan@broadcom.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>