topology/sysfs: export die attributes only if an architectures has support

topology/sysfs: export die attributes only if an architectures has support

The die_id and die_cpus topology sysfs attributes have been added with
commit 0e344d8c709f ("cpu/topology: Export die_id") and commit
2e4c54dac7b3 ("topology: Create core_cpus and die_cpus sysfs attributes").

While they are currently only used and useful for x86 they are still
present with bogus default values for all architectures. Instead of
enforcing such new sysfs attributes to all architectures, make them
only optional visible if an architecture opts in by defining both the
topology_die_id and topology_die_cpumask attributes.

This is similar to what was done when the book and drawer topology
levels were introduced: avoid useless and therefore confusing sysfs
attributes for architectures which cannot make use of them.

This should not break any existing applications, since this is a
rather new interface and applications should be able to handle also
older kernel versions without such attributes - besides that they
contain only useful information for x86.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Link: https://lore.kernel.org/r/20211129130309.3256168-2-hca@linux.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>