net/cadence/macb: Simplify OF dependencies

With of_get_mac_address() and of_get_phy_mode() now defined as dummy
functions if OF_NET is not configured, it is no longer necessary to
provide OF dependent functions as front-end. Also, the two functions
depend on OF_NET, not on OF, so the conditional code was not correct
anyway.

Drop the front-end functions and call of_get_mac_address() and
of_get_phy_mode() directly instead.

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