sparse: remove unnecessary 0 values from rc

rc is assigned first, so it does not need to initialize the
assignment.

Link: https://lkml.kernel.org/r/20230421214733.2909-1-zeming@nfschina.com
Signed-off-by: Li zeming <zeming@nfschina.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: Li zeming

mm/sparse.c

@@ -832,7 +832,7 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn,
 	struct mem_section *ms = __pfn_to_section(pfn);
 	struct mem_section_usage *usage = NULL;
 	struct page *memmap;
-	int rc = 0;
+	int rc;
 
 	if (!ms->usage) {
 		usage = kzalloc(mem_section_usage_size(), GFP_KERNEL);