net: stmmac: use dev_info() before netdev is registered

Before the netdev is registered, calling netdev_info() will emit
something as "(unnamed net device) (uninitialized)", looks confusing.

Before this patch:
[    3.155028] stmmaceth f7b60000.ethernet (unnamed net_device) (uninitialized): device MAC address 52:1a:55:18:9e:9d

After this patch:
[    3.155028] stmmaceth f7b60000.ethernet: device MAC address 52:1a:55:18:9e:9d

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Signed-off-by: David S. Miller <davem@davemloft.net>