e1000e: Make arrays out of these Rx/Tx registers

With multiple queues coming into the code these base control
registers need to be made into arrays.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Auke Kok <auke-jan.h.kok@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>