spi: dt-bindings: snps,dw-apb-ssi: Add compatible for Intel Mount Evans SoC

Document the DesignWare SSI controller compatible for Intel Mount Evans
Integrated Management Complex SoC.

Signed-off-by: Abe Kohandel <abe.kohandel@intel.com>
Link: https://lore.kernel.org/r/20230606145402.474866-3-abe.kohandel@intel.com


Signed-off-by: Mark Brown <broonie@kernel.org>