device monitor return non-usb midi devices

[TheTechnobear]

see #527

expose non-usb midi devices e.g. gpio

[catfact]

i still don't like this:

• it means that when running the code on a laptop, we get a lot of noise and confusion as norns attempts to use all the other TTY and HID devices. the subsystem check is there for the simple reason that we would like to ignore these and have a similar experience when testing norns code on laptop as on norns HW.

• the change has no application to the norns hardware. i'm also failing to see how it has much application on other, hypothetical hardware - the entire point of device_monitor.c is to monitor hotplugged devices; if you are using some other hardware with persistent GPIO midi, why do you need to detect it?

all thatn said, i don't have a huge problem with merging this and skipping the subsystem checks, if anyone else sees a benefit.

[TheTechnobear]

ok, I'll withdraw
seems my use-cases are not relevant to norns.