drivers: net: cpsw: don't ignore phy-mode if phy-handle is used

The phy-mode emac property was only being processed in the phy_id
or fixed-link cases. However if phy-handle was specified instead,
an error message would complain about the lack of phy_id or
fixed-link, and then jump past the of_get_phy_mode(). This would
result in the PHY mode defaulting to MII, regardless of what the
devicetree specified.

Fixes: 9e42f715

 ("drivers: net: cpsw: add phy-handle parsing")
Signed-off-by: David Rivshin <drivshin@allworx.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Tested-by: Andrew Goodbody <andrew.goodbody@cambrionix.com>
Reviewed-by: Mugunthan V N <mugunthanvnm@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>