chore: update all SPI usage to use either *machine.SPI or drivers.SPI

[deadprogram]

This PR is to update all SPI usage to use either *machine.SPI or drivers.SPI to accommodate recent switch in machine package to always use *machine.SPI.

[gandarez]

Wouldn't this introduce a breaking change since we are changing the NewXXX() funcs to accept an interface as param?

[deadprogram]

@gandarez that is potentially true, however it is already something we have been moving towards with the I2C interface, for example.

The benefit is greater compatibility in the future, and also ability to write tests such as that proposed in PR #742

[gandarez]

What's the rationale to decide between machine or drivers package?

[deadprogram]

I would like to switch entirely to use drivers.SPI so that it is testable interface and also no dependency on the TinyGo machine package.

However, some current drivers are calling specific SPI methods and I did not want to have to address that problem at the same time, which is why I did not change all of them to use drivers.SPI in this PR.

[deadprogram]

Thanks for review @gandarez now merging.