Complete 1020 pin impls

#30 introduced 1020 pads, and implementations for a few peripherals. This issue tracks complete pin implementations for the 1020.

- [ ] ADC
- [x] CCM
- [ ] FlexCAN
- [ ] FlexIO
- [ ] FlexPWM
- [x] GPIO
- [x] LPI2C
- [x] LPSPI
- [x] LPUART
- [ ] SAI
- [ ] USDHC

Checks indicate complete support for a peripheral. Unchecked peripherals have incomplete or no support.