Summary

According to Intel Advanced/RU's specs, this supports 4MB RAM memory, so this PR corrects the memory step for that machine.

Checklist

• Closes #xxx
• I have tested my changes locally and validated that the functionality works as intended
• I have discussed this with core contributors already
• This pull request requires changes to the ROM set
  • I have opened a roms pull request - https://github.com/86Box/roms/pull/changeme/

References

Intel Advanced/RU specs