Revert "phylib: remove a couple of redundant code lines"

Revert "phylib: remove a couple of redundant code lines"

This reverts commit 041c542219af7f31c372d89b4c7c6f4c8064a8ce.

The lines removed by this commit weren't redundant. The logic is (and
probably should be better commented):

Find the intersection of the advertised capabilities of both sides of
the link (lpa).
From that intersection, find the highest capability we can run at
(that will be the negotiated link).

Now imagine that the intersection (lpa) is (LPA_100HALF | LPA_10FULL).

The code will now set phydev->speed to 100, and phydev->duplex to 1,
but this link does not support 100FULL.

Kudos to Andy Fleming <afleming@gmail.com> for binging this to
attention and for the explanation.

Signed-off-by: Wolfgang Denk <wd@denx.de>