otPlatDiagGpioGet() function

OT_ERROR_NONE Successfully got the gpio value. OT_ERROR_FAILED A platform error occurred while getting the gpio value. OT_ERROR_INVALID_ARGS @p aGpio is not supported or @p aValue is NULL. OT_ERROR_INVALID_STATE Diagnostic mode was not enabled or @p aGpio is not configured as input. OT_ERROR_NOT_IMPLEMENTED This function is not implemented or configured on the platform.