net: dsa: sja1105: implement .devlink_info_get

Return the driver name and ASIC ID so that generic user space
application are able to know they're looking at sja1105 devlink regions
when pretty-printing them.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>