memblock: Return NUMA_NO_NODE instead of -1 to improve code readability

When no corresponding memory region is found for the given pfn, return
NUMA_NO_NODE instead of -1. This improves code readability and aligns with
the existing logic of the memblock_search_pfn_nid() function's user.

Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Link: https://lore.kernel.org/r/20231207131001.224914-1-ytcoode@gmail.com
Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Author: ytcoode

mm/memblock.c

@@ -1851,7 +1851,7 @@ int __init_memblock memblock_search_pfn_nid(unsigned long pfn,
 	int mid = memblock_search(type, PFN_PHYS(pfn));
 
 	if (mid == -1)
-		return -1;
+		return NUMA_NO_NODE;
 
 	*start_pfn = PFN_DOWN(type->regions[mid].base);
 	*end_pfn = PFN_DOWN(type->regions[mid].base + type->regions[mid].size);