Corrected pin offset (for other raspis than pi5)

[4ltfour]

This module isn't currently working on (in my case) raspberry pi 4.
When MM is started this error message is shown:

[2025-05-10 09:03:49.013] [LOG] MMM-Buttons: RPi model Raspberry Pi 4 Model B Rev 1.5
[2025-05-10 09:03:49.022] [ERROR] Whoops! There was an uncaught exception...
[2025-05-10 09:03:49.043] [ERROR] Error: EINVAL: invalid argument, write
at Object.writeFileSync (node:fs:2426:20)
at exportGpio (/home/user/MagicMirror/modules/MMM-Buttons/node_modules/onoff/onoff.js:18:8)
at new Gpio (/home/user/MagicMirror/modules/MMM-Buttons/node_modules/onoff/onoff.js:172:36)
at Class.intializeButton (/home/user/MagicMirror/modules/MMM-Buttons/node_helper.js:89:19)
at Class.intializeButtons (/home/user/MagicMirror/modules/MMM-Buttons/node_helper.js:105:18)
at Class.socketNotificationReceived (/home/user/MagicMirror/modules/MMM-Buttons/node_helper.js:28:18)
at Socket. (/home/user/MagicMirror/js/node_helper.js:91:10)
at Socket.onevent (/home/user/MagicMirror/node_modules/socket.io/dist/socket.js:462:26)
at Socket._onpacket (/home/user/MagicMirror/node_modules/socket.io/dist/socket.js:430:22)
at /home/user/MagicMirror/node_modules/socket.io/dist/client.js:214:24
at process.processTicksAndRejections (node:internal/process/task_queues:85:11) {
errno: -22,
code: 'EINVAL',
syscall: 'write'
}

Thanks to this stack overflow thread, I found that the pin offset for the Pi 5 is set, but not for every other Pi.

Added correct pin offset for other raspberry pis than the pi5.

[KristjanESPERANTO]

@MarcLandis Did you noticed this PR? 🙂