ARM: dts: aspeed: Add ASRock SPC621D8HM3 BMC

ARM: dts: aspeed: Add ASRock SPC621D8HM3 BMC

This is a Xeon board broadly similar (aside from CPU vendor) to the
already-support romed8hm3 (half-width, single-socket, ast2500).  It
doesn't require anything terribly special for OpenBMC support, so this
device-tree should provide everything necessary for basic
functionality with it.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
Link: https://lore.kernel.org/r/20231120121954.19926-6-zev@bewilderbeest.net
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>