ARM: dts: aspeed: Add AST2600 EDAC into common devicetree

Add Aspeed AST2600 EDAC node into the common devicetree.

Signed-off-by: Troy Lee <troy_lee@aspeedtech.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lkml.kernel.org/r/20201207090013.14145-2-troy_lee@aspeedtech.com