mm: vmalloc: correct use of __GFP_NOWARN mask in __vmalloc_area_node()

This function sets __GFP_NOWARN in the gfp_mask rendering the warn_alloc()
invocations no-ops.  Remove this and instead rely on this flag being set
only for the vm_area_alloc_pages() function, ensuring it is cleared for
each of the warn_alloc() calls.

Link: https://lkml.kernel.org/r/20221219123659.90614-1-lstoakes@gmail.comSigned-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/vmalloc.c

@@ -3031,7 +3031,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
 	int ret;
 
 	array_size = (unsigned long)nr_small_pages * sizeof(struct page *);
-	gfp_mask |= __GFP_NOWARN;
+
 	if (!(gfp_mask & (GFP_DMA | GFP_DMA32)))
 		gfp_mask |= __GFP_HIGHMEM;