net/atlantic: remove unused variable
net/atlantic: remove unused variable

Found by coverity scan.

Coverity issue: 323512
Fixes: 7906661edac6 ("net/atlantic: add b0 hardware layer")
Cc: stable@dpdk.org

Signed-off-by: Igor Russkikh <84bb31e89044ad5cf75616997932933f48af3f9a@aquantia.com>

john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk,john-mcnamara-intel/dpdk