Description: mm/demotion: fix NULL vs IS_ERR checking in memory_tier_init
References:
Notes:
 carnil> Commit fixes 7b88bda3761b ("mm/demotion/dax/kmem: set node's
 carnil> abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE") in 6.1-
 carnil> rc1.
Bugs:
upstream: released (6.2-rc1) [4a625ceee8a0ab0273534cb6b432ce6b331db5ee]
6.1-upstream-stable: needed
5.10-upstream-stable: N/A "Vulnerable code not present"
4.19-upstream-stable: N/A "Vulnerable code not present"
sid: released (6.3.7-1)
6.1-bookworm-security: needed
5.10-bullseye-security: N/A "Vulnerable code not present"
4.19-buster-security: N/A "Vulnerable code not present"