RP2350 - support for a 3rd PIO instance

[k7bbr]

Thanks for adding support for the RP2040 as well as #873 adding support for 2 PIO instances. How hard would it be to add support for a 3rd PIO instance for the RP2350?

[Makuna]

What board support are you using?

I don't have a RP2350 to test with, but the changes look pretty boiler plate.

Try this branch and let me know if it works.

https://github.com/Makuna/NeoPixelBus/tree/RP2350

[k7bbr]

Currently using the Pico 2 with an RP2350 chip. I'll try that branch and report back. Thanks.

[k7bbr]

That branch worked great! All 12 Pio outputs working fine across all 3 Pio instances on a Raspberry Pi Pico 2. Thank you!

[Makuna]

created a tracking issue and merged the changes into master for the next release