[PATCHES] bsps/imxrt: Support GPIO CS for LPSPI; Minor fix for imxrt1166

[Christian Mauderer]

Hello,

with this patch set, the LPSPI of the imxrt BSPs now can use a GPIO as a
chip select pin. The documentation is updated to show how it works.

Additionally a minor fix for the iomux for the imxrt1166 is added. On
that BSP some pins have been initialized that shouldn't be initialized
unless someone explicitly uses the peripheral.

Best regards

Christian