powerpc/pseries: Add a helper for form1 cpu distance

stable inclusion
from stable-v5.10.178
commit 498618e0a1e779f22cfa3bcf2497244bc7bace5a
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8D927

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=498618e0a1e779f22cfa3bcf2497244bc7bace5a



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[ Upstream commit ef31cb83 ]

This helper is only used with the dispatch trace log collection.
A later patch will add Form2 affinity support and this change helps
in keeping that simpler. Also add a comment explaining we don't expect
the code to be called with FORM0

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210812132223.225214-5-aneesh.kumar@linux.ibm.com


Stable-dep-of: b277fc79 ("powerpc/papr_scm: Update the NUMA distance table for the target node")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: sanglipeng <sanglipeng1@jd.com>