Enable SOC_SIFIVE so the default upstream config is bootable on the SiFive
Unleashed Board.
And have basic support for future boards based on the same SoC.
Signed-off-by: NLoys Ollivier <lollivier@baylibre.com>
Reviewed-by: NPalmer Dabbelt <palmer@sifive.com>
[paul.walmsley@sifive.com: updated to apply]
Signed-off-by: NPaul Walmsley <paul.walmsley@sifive.com>