DOS: read_bios_keystate() adaptation for PC-98 targets, to ease code migration
DOS: read_bios_keystate() adaptation for PC-98 targets, to ease code migration

joncampbell123/doslib,joncampbell123/doslib,joncampbell123/doslib,joncampbell123/doslib,joncampbell123/doslib,joncampbell123/doslib