e100: Fix passing zero to 'PTR_ERR' warning in e100_load_ucode_wait

Fix a static code checker warning:
drivers/net/ethernet/intel/e100.c:1349
 e100_load_ucode_wait() warn: passing zero to 'PTR_ERR'

Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>