net/freescale/fec: Simplify OF dependencies

Since of_get_mac_address() is now defined even if CONFIG_OF_NET
is not configured, the ifdef around the code calling it is no longer
necessary and can be removed.

Similar, since of_get_phy_mode() is now defined as dummy function
if OF_NET is not configured, it is no longer necessary to provide
an OF dependent function as front-end. Also, the function depends
on OF_NET, not on OF, so the conditional code was not correct anyway.
Drop the front-end function and call of_get_phy_mode() directly.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: David S. Miller <davem@davemloft.net>