Description: powerpc/mm: Fix null-pointer dereference in pgtable_cache_add
References:
Notes:
 carnil> First introducing commit could not be determined.
Bugs:
upstream: released (6.8-rc1) [f46c8a75263f97bda13c739ba1c90aced0d3b071]
6.7-upstream-stable: released (6.7.4) [ffd29dc45bc0355393859049f6becddc3ed08f74]
6.6-upstream-stable: released (6.6.16) [145febd85c3bcc5c74d87ef9a598fc7d9122d532]
6.1-upstream-stable: released (6.1.77) [d482d61025e303a2bef3733a011b6b740215cfa1]
5.10-upstream-stable: released (5.10.210) [aa28eecb43cac6e20ef14dfc50b8892c1fbcda5b]
4.19-upstream-stable: released (4.19.307) [21e45a7b08d7cd98d6a53c5fc5111879f2d96611]
sid: released (6.7.7-1)
6.1-bookworm-security: released (6.1.82-1)
5.10-bullseye-security: needed
4.19-buster-security: ignored "powerpc not supported in LTS"