mm: Rename pmd_read_atomic()

There's no point in having the identical routines for PTE/PMD have
different names.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221022114424.841277397%40infradead.org
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 3d0fef3..89a1c9c 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -630,7 +630,7 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
 			break;
 		}
 
-		dst_pmdval = pmd_read_atomic(dst_pmd);
+		dst_pmdval = pmdp_get_lockless(dst_pmd);
 		/*
 		 * If the dst_pmd is mapped as THP don't
 		 * override it and just be strict.