Implement SInput controller serial number

[slouken]

The serial number for the SInput controllers should be the Bluetooth MAC address, separated by dashes, as is done with the 8BitDo controllers, for consistency. It should be set in both wired and Bluetooth mode so it can be identified as the same device in both modes, possibly included in the handshake packet? @mitchellcairns, can you take a look?

[mitchellcairns]

Resolved with #13387

[slouken]

The serial number is in reverse order and doesn't quite match the Bluetooth MAC address.

[mitchellcairns]

As it turned out, ESP32 was adding 2 to the last octet of the mac address (Adding 1 for each wireless endpoint; Wifi, AP, Bluetooth, etc)

Resolved with HandHeldLegend/HOJA-ESP32-Baseband@59621c0

Reference: https://docs.espressif.com/projects/esp-idf/en/stable/esp32/api-reference/system/misc_system_api.html#mac-address

[slouken]

Confirmed fixed!