dt-bindings: EDAC: Add Amazon's Annapurna Labs Memory Controller binding

Document Amazon's Annapurna Labs Memory Controller EDAC SoC binding.

Signed-off-by: Talel Shenhar <talel@amazon.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lkml.kernel.org/r/20200816185551.19108-2-talel@amazon.com