Set SPI CLK pin pull up/down in SPI Configure based on SPI polarity config

[sgauche]

If the SPI CLK polarity is set to 1, then a pull up resistor is required to keep the CLK signal high when the CLK goes to tri-state during idle periods. The pull up resistor could be external, but if your board is hard to modify, then setting the internal pull up resistor on the SPI CLK pin is useful. As the SPI CLK pin gets set up as a busio it becomes marked as "in use" and you can't manually set it to a pull up/down using digitalio, so the pull up/down should be set on spi configure.

[sgauche]

Blue: Chip select
Yellow: SPI CLK (SCK)

Before change, you can see SCK is not driven until after chip select is driven active low, and then SCK is set back to tri-state before chip select is driven high again:

After change, SCK is idle high before chip select is driven active low and remains idle high after the transaction too:

[tannewt]

Looks good to me! Thank you!