lscpu: add nooverwrite flag for ARM implementer table

lscpu: add nooverwrite flag for ARM implementer table

Add a nooverwrite flag to struct hw_impl. When set, vendor and model
name already provided by the kernel in /proc/cpuinfo are preserved
rather than being overwritten by the hardcoded lookup tables. The
tables serve as a fallback when the kernel does not provide the
information.

This approach keeps all implementer entries in the table, which is
also required for "lscpu --arm-id" to list all known vendors and
part IDs.

Addresses: https://github.com/util-linux/util-linux/pull/4362
Signed-off-by: Karel Zak <kzak@redhat.com>