MLK-21054-3 pinctrl: Enable imx8mq support

Copy pin header from rel_imx_4.14.98_2.0.0_ga_rc1 and enable
compilation. The C code of the driver was already accepted in v4.19 in
an acceptable form so we use that.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>