net: bnx2: Fix error return code in bnx2_init_board()

Fix to return -EPERM from the error handling case instead of 0, as done
elsewhere in this function.

Fixes: b6016b76

 ("[BNX2]: New Broadcom gigabit network driver.")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Reviewed-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>