Add documentation describing the device-tree properties for the Parrot pinctrl driver. Change-Id: Id8b6bfc598f747860aede2b03ea76ffd27036a96 Signed-off-by: Naina Mehta <quic_nainmeht@quicinc.com> Signed-off-by: Swetha Chikkaboraiah <quic_schikk@quicinc.com>