mm/memory-failure: simplify put_ref_page()

mm/memory-failure: simplify put_ref_page()

Patch series "Some cleanups for memory-failure", v3.

This series contains a few cleanup patches to avoid exporting unused
function, add helper macro, fix some obsolete comments and so on.  More
details can be found in the respective changelogs.

This patch (of 13):

Remove unneeded page != NULL check.  pfn_to_page() won't return NULL.  No
functional change intended.

Link: https://lkml.kernel.org/r/20240612071835.157004-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20240612071835.157004-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>