firmware: xilinx: Add configuration values for tri-state

Add configuration values(enable/disable) for tri-state parameter.

Signed-off-by: Sai Krishna Potthuri <lakshmi.sai.krishna.potthuri@xilinx.com>
Link: https://lore.kernel.org/r/1655462819-28801-2-git-send-email-lakshmi.sai.krishna.potthuri@xilinx.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>