Is your feature request related to a problem? Please describe.
86Box is missing PCI54ST emulation.

Describe the solution you'd like:
I would like 86Box to emulate the PCI54ST motherboard.

Additional context:
The PCI54ST had these specs:

• Socket 7.
• SiS 551X chipset.
• 256K/512K/1M external cache.
• Support for PS/2 mice.