mm: remove redundant return in set_huge_zero_folio()

mm: remove redundant return in set_huge_zero_folio()

It is the responsibility of the caller to check pmd_none(); in any case,
we are not achieving anything by returning since there is no return value
to tell the caller that we succeeded or not.  So remove this check.

Link: https://lkml.kernel.org/r/20250306144315.21907-1-dev.jain@arm.com
Signed-off-by: Dev Jain <dev.jain@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>