ixgbe: correct the parameter description

ccffad25b5136958d4769ed6de5e87992dd9c65c changed parameters for function
ixgbe_update_uc_addr_list_generic but parameter description was not updated.
This patch corrects it.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Acked-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>