pinctrl: single: Parse gpio details from dt

Parse different gpio properties from dt as part of probe
function. This detail is required to enable pinctrl pad
later when gpio lines are requested.

Signed-off-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Signed-off-by: Bharat Gooty <bharat.gooty@broadcom.com>
Acked-by: Rayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>