You just have one of those Motherboards that shares nearly everything over one IRQ, which is next to no big deal at all.
Your problem is much bigger: the tulip driver has nothing to do with Linksys's wireless PCMCIA card and adapter. I've gotten the drivers from the Linux Wlan project to work with Slack 7.1, 2.2.16 kernel, and those exact same two pieces of hardware, albeit probably with a little older firmware. There are three projects that may work with this combination of PLX card and wireless antenna, although they're all linked off of this site, which is also a monster resource as far as all of this wireless gunk is concerned:
Jean Tourrilhes page.
Honestly, I only ever got that combo of PLX card and antenna to work once, with that one set-up, and only in managed mode, although part of my problem may have been dated firmware.
Cheers,
Finegan