igb: remove check for needing an io port

Since igb supports only pci-e nics and there is no plan to support any
legacy pci parts in the driver there isn't really much need for checking to
see if an io port is needed.

In the unlikely event that we do begin supporting legacy pci parts then we
can see about adding this code back to the driver.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>