starfire: use BUILD_BUG_ON for netdrv_addr_t

Detect size mismatch for netdrv_addr_t at build time rather than
checking at module load time.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Ion Badulescu <ionut@badula.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>