net: fec: set phy_of_node properly for fixed-link phy

If the FEC is connected to a fixed-link (upstream switch port for
example) the phy_of_node should be set to the fixed-link node
so that speed and other properties can be found properly.

In addition fix a typo in the debug string.

Signed-off-by: Tim Harvey <tharvey@gateworks.com>
Reviewed-by: Ramon Fried <rfried.dev@gmail.com>