Add kconfig options for rp2040 uart

[amken3d]

Current implementation only supports UART0 on Pin0 and 1. This change brings in all the possible UART 0 and 1 pin combinations for the RP2040. Has been tested on a custom board with UART1 on 24,25

[JamesH1978]

Thank you for submitting a PR, pleas refer to point 3 in "What to expect in a review" in https://github.com/Klipper3d/klipper/blob/master/docs/CONTRIBUTING.md and provide a signed off by line.

Thanks James

[amken3d]

I have included the sign off line for each commit and rebased. Thank you

[amken3d]

@KevinOConnor, thank you for the feedback. I have made the changes you suggested.

[amken3d]

Done

[KevinOConnor]

Thanks.

-Kevin