ras-arm-handler: be compatible with upstream Kernel

ras-arm-handler: be compatible with upstream Kernel

Changeset e37eb2f11a82 ("Add code to decode Ampere specific error")
broke ARM event record with upstream Kernel, as it requires a different
trace event than the one that it is on upstream Kernel, and it is
part of a pending pull request:

	https://lore.kernel.org/all/20240321-b4-arm-ras-error-vendor-info-v5-rc3-v5-0-850f9bfb97a8@os.amperecomputing.com/

Restore its behavior by making parsing the UEFI 2.6+ N.17 and N.16
table extra fields to be optional. That should make it compatible
with current upstream Kernels again.

Fixes: e37eb2f11a82 ("Add code to decode Ampere specific error")
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>