dts: riscv32-litex-vexriscv.dtsi: drop 'spinalhdl' compatible

This has an unrecognized vendor prefix which does not seem to serve
any purpose. Removing it is a way forward to turning warnings into
errors on unrecognized vendor prefixes.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
1 file changed