The intention is to replace GATEWARE_GIT_VERSION within the "chosen" section
of the device tree overlay with git hash/branch/tag gateware
repository information to help identify the gateware version at
run time.

Allow the control of M2_UART_RTS and M2_UART_CTS from the CorePGIO
instance used for board tests of the M.2 connector.

- Correct the number of gpios and gpio controller's base address in dts.
- Loopback the gpios outputs to the inputs so that the output values is
read back from software (avoids the outputs looking like they are not
working).