e1000e: increase rx fifo size to 36K on 82574 and 82583

e1000e: increase rx fifo size to 36K on 82574 and 82583

This change increases the RX fifo size to 36K for standard frames and
decreases the TX fifo size to 4K.  The reason for this change is that on
slower systems the RX is much more likely to backfill and need space than
the TX is.  As long as the TX fifo is twice the size of the MTU we should
have more than enough TX fifo.

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>