dts: arm: nxp_kw2xd: Add SPI0 sip pins As the KW2XD is a SiP (System-in-package) the SPI1 controller on the MCU is connected to the modem. As the pinctrl details for this in the SoC dtsi file as these pins are not exposed in the pindata XMLs from NXP. Signed-off-by: Kumar Gala <kumar.gala@linaro.org>