[ Upstream commit 3b025f2b ]

Enable PRCI clock driver and serial console by default, so the default
upstream defconfig is bootable to a serial console.
Signed-off-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>