mm/mm_init.c: update obsolete comment in get_pfn_range_for_nid()

Since commit 633c0666 ("Memoryless nodes: drop one memoryless node boot
warning"), the warning for a node with no available memory is removed.
Update the corresponding comment.

Link: https://lkml.kernel.org/r/20230625033340.1054103-1-linmiaohe@huawei.comSigned-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/mm_init.c

@@ -1681,8 +1681,7 @@ static inline void alloc_node_mem_map(struct pglist_data *pgdat) { }
  *
  * It returns the start and end page frame of a node based on information
  * provided by memblock_set_node(). If called for a node
- * with no available memory, a warning is printed and the start and end
- * PFNs will be 0.
+ * with no available memory, the start and end PFNs will be 0.
  */
 void __init get_pfn_range_for_nid(unsigned int nid,
 			unsigned long *start_pfn, unsigned long *end_pfn)