separate partition format handling from generic code

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/block/partitions/check.h b/block/partitions/check.h
index d68bf4d..52b1003 100644
--- a/block/partitions/check.h
+++ b/block/partitions/check.h
@@ -22,6 +22,9 @@
 	char *pp_buf;
 };
 
+struct parsed_partitions *
+check_partition(struct gendisk *, struct block_device *);
+
 static inline void *read_part_sector(struct parsed_partitions *state,
 				     sector_t n, Sector *p)
 {