[intel] Add workaround for I210 reset hardware bugs

[intel] Add workaround for I210 reset hardware bugs

The Intel I210's packet buffer size registers reset only on power up,
not when a reset signal is asserted.  This can lead to the inability
to pass traffic in the event that the DMA TX Maximum Packet Size
(which does reset to its default value on reset) is bigger than the TX
Packet Buffer Size.

For example, an operating system may be using the time sensitive
networking features of the I210 and the registers may be programmed
correctly, but then a reset signal is asserted and iPXE on the next
boot will be unable to use the I210.

Mimic what Linux does and forcibly set the registers to their default
values.

Signed-off-by: Matt Parrella <parrella.matthew@gmail.com>