[SeaBIOS] [PATCH] Support multiple USB HID keyboards/mice

[Daniel Khodabakhsh]

This change allows the use of multiple USB HID keyboards and mice.
It's similar to the change by Stef van Os from this thread:

https://mail.coreboot.org/hyperkitty/list/[e-mail]/thread/O6Y4LUK...

however this new change uses the linked list approach instead of a fixed array.

Tested on QEMU and an Asus KGPE-D16 with 2 keyboards and one mice