asmc: add Wake-on-LAN control via sysctl

[seuros_seuros.com]

Summary

Apple Mac systems support Wake-on-LAN from powered-off state (S5/G2) via the AUPO SMC key.

This change adds a convenience sysctl:

dev.asmc.0.wol (0=disabled, 1=enabled)

The AUPO key is volatile and resets to 0x00 on every boot, so WoL must be manually enabled before each shutdown to work from powered-off state.
Users need to run:
sysctl dev.asmc.0.wol=1
before shutting down the system.

Test Plan

Tested on Mac Mini 5,1 (FreeBSD 16.0-CURRENT):

1. Boot system, check default WoL state:

• sysctl dev.asmc.0.wol
• Expected: 0 (disabled - AUPO resets on boot)

2. Enable WoL before shutdown:

• sudo sysctl dev.asmc.0.wol=1
• Expected: Returns 1, no errors

3. Verify AUPO was set:

• sudo sysctl dev.asmc.0.wol
• Expected: 1

4. Shutdown system:

• sudo shutdown -p now

5. From another machine, send magic packet:

• wakeonlan -i 192.168.3.255 <MAC_ADDRESS> <-- use your local ip range
• Expected: System powers on and boots

6. After boot, verify WoL state reset:

• sysctl dev.asmc.0.wol
• Expected: 0 (AUPO volatile, resets on boot)

7. Test disable: (it disabled by default)

• sudo sysctl dev.asmc.0.wol=1
• sudo sysctl dev.asmc.0.wol=0
• sudo shutdown -p now
• Send magic packet

Note: My thunderbird ethernet cable is broken, so i could not test it in the laptops.

The user need to build rc.d integration or shutdown hook to keep the value set to 1

[seuros_seuros.com]

i got the patch from the wrong branch, the first time.