Formally grant SPI CS pin for any purpose if not used for SPI

[sadekbaroudi]

Credit to @george-norton for the idea

The SPI CS in the VIK connector is intended for that purpose. However, if it's not used in the module, is there really any reason to not grant permission for the module to use as a general digital IO pin?

In every other case, this doesn't make sense, except for SPI CS

For I2C, you would disrupt the bus by using for any other purpose
For the other 3 SPI pins (MISO, MOSI, SCLK), you would also disrupt the bus by using for any other purpose
For RGB, you can't be sure that the main pcb isn't using it for RGB already, rendering it useless for any other purpose
For the other two general analog/digital GPIO, they're already free to use.

There really aren't any clear downsides to officially granting access to the module to SPI CS as a 3rd digital GPIO.