[coreboot] [PATCH] amdk8_util documentation (and one fix)

[Myles Watson]

This is the real fix.  The method returns a 0 instead of a NULL list
if there are no resources found.  This makes it match the other
methods.

-			Store (BUF0, Local3)
+			Store (RTAG (BUF0), Local3)

The rest of the patch is documentation because I find it hard to
understand asl without comments.

Signed-off-by: Myles Watson

Thanks,
Myles