spi: Tesla FSD support

Merge series from Alim Akhtar:

This series adds support for the SPI controller in the Tesla FSD SoC,
also pulling in:

   git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git ib-mfd-spi-dt-v5.18

from the MFD tree which has dependencies for the DT bindings.