Have rgephy(4) always use RL_GMEDIASTAT to retrieve the link/media status

Have rgephy(4) always use RL_GMEDIASTAT to retrieve the link/media status
when attached to re(4), as was done before rev 1.25 which was intended to
fix rgephy(4) with external PHY with MACs other than re(4). This is to
fix operation with some integrated PHY on re(4) where the PHY Specific
Status register does not work properly and the link cannot be established.

From FreeBSD and matches what the Linux driver does.

Tested on a number of newer re(4) with PHYs rev 2, 4 and 5 and
newer integrated PHY with the 8168G controllers.