EDAC, mce_amd: Print ExtErrorCode and description on a single line

Save a log line by printing the extended error code and the description
on a single line. This is similar to how errors are printed in other
subsystems, e.g. "#, description". If we don't have a valid description
then only the number/code is printed.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86@kernel.org
Link: https://lkml.kernel.org/r/20190201225534.8177-6-Yazen.Ghannam@amd.com