EDAC/amd64: Recognize x16 symbol size

Future AMD systems may support x16 symbol sizes.

Recognize if a system is using x16 symbol size. Also, simplify the print
statement.

Note that a x16 syndrome vector table is not necessary like with x4 or
x8 syndromes. This is because systems that support x16 symbol sizes are
SMCA systems and in that case, the syndrome can be directly extracted
from the MCA_SYND[Syndrome] field.

 [ bp: massage. ]

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Tested-by: Kim Phillips <kim.phillips@amd.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-edac <linux-edac@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190228153558.127292-4-Yazen.Ghannam@amd.com