eth: fealnx: bring back this old driver

eth: fealnx: bring back this old driver

This reverts commit d5e2d038dbece821f1af57acbeded3aa9a1832c1.

We have a report of this chip being used on a

  SURECOM EP-320X-S 100/10M Ethernet PCI Adapter

which could still have been purchased in some parts
of the world 3 years ago.

Cc: stable@vger.kernel.org
Link: https://bugzilla.kernel.org/show_bug.cgi?id=217151
Fixes: d5e2d038dbec ("eth: fealnx: delete the driver for Myson MTD-800")
Link: https://lore.kernel.org/r/20230307171930.4008454-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>