block: Handle partition read errors more consistently

Set p->v to NULL if we try to read beyond the end of the disk, just like
we do if we get an error returned from trying to read the disk.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

block/partitions/core.c

@@ -709,7 +709,7 @@ void *read_part_sector(struct parsed_partitions *state, sector_t n, Sector *p)
 
 	if (n >= get_capacity(state->disk)) {
 		state->access_beyond_eod = true;
-		return NULL;
+		goto out;
 	}
 
 	page = read_mapping_page(mapping,