lan743x: remove redundant intializations of pointers adapter and phydev

The pointers adapter and phydev are being initialized with values that
are never read and are being updated later with a new value. The
initialization is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>