The Witherspoon BMC is an ASPEED ast2500 based BMC that is part of an
OpenPower Power9 server.

This adds the device tree description for most upstream components. It
is a squashed commit from the OpenBMC kernel tree.
Signed-off-by: NBrandon Wyman <bjwyman@gmail.com>
Signed-off-by: NMatt Spinler <spinler@us.ibm.com>
Signed-off-by: NBrad Bishop <bradleyb@fuzziesquirrel.com>
Signed-off-by: NEdward A. James <eajames@us.ibm.com>
Signed-off-by: NCédric Le Goater <clg@kaod.org>
Signed-off-by: NAndrew Jeffery <andrew@aj.id.au>
Reviewed-by: NBrandon Wyman <bjwyman@gmail.com>
Signed-off-by: NJoel Stanley <joel@jms.id.au>