hinic: Remove unused variable.

drivers/net/ethernet/huawei/hinic/hinic_hw_mgmt.c: In function ‘mgmt_recv_msg_handler’:
drivers/net/ethernet/huawei/hinic/hinic_hw_mgmt.c:443:18: warning: unused variable ‘pdev’ [-Wunused-variable]
  443 |  struct pci_dev *pdev = pf_to_mgmt->hwif->pdev;
      |                  ^~~~

Signed-off-by: David S. Miller <davem@davemloft.net>