amd64_edac: Reorganize error reporting path

Rewrite CE/UE paths so that they use the same code and drop additional
code duplication in handle_ue. Add a struct err_info which collects
required info for the error reporting. This, in turn, helps slimming all
edac_mc_handle_error() calls down to one.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>