net/ncsi: Add NC-SI 1.2 Get MC MAC Address command

This change adds support for the NC-SI 1.2 Get MC MAC Address command,
specified here:

https://www.dmtf.org/sites/default/files/standards/documents/DSP0222_1.2.0.pdf



It serves the exact same function as the existing OEM Get MAC Address
commands, so if a channel reports that it supports NC-SI 1.2, we prefer
to use the standard command rather than the OEM command.

Verified with an invalid MAC address and 2 valid ones:

[   55.137072] ftgmac100 1e690000.ftgmac eth0: NCSI: Received 3 provisioned MAC addresses
[   55.137614] ftgmac100 1e690000.ftgmac eth0: NCSI: MAC address 0: 00:00:00:00:00:00
[   55.138026] ftgmac100 1e690000.ftgmac eth0: NCSI: MAC address 1: fa:ce:b0:0c:20:22
[   55.138528] ftgmac100 1e690000.ftgmac eth0: NCSI: MAC address 2: fa:ce:b0:0c:20:23
[   55.139241] ftgmac100 1e690000.ftgmac eth0: NCSI: Unable to assign 00:00:00:00:00:00 to device
[   55.140098] ftgmac100 1e690000.ftgmac eth0: NCSI: Set MAC address to fa:ce:b0:0c:20:22

Signed-off-by: Peter Delevoryas <peter@pjd.dev>
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Signed-off-by: David S. Miller <davem@davemloft.net>