pstore: Make "part" unsigned

We'll never have a negative part, so just make this an unsigned int.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 12be8f1..cc03bbf 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -39,7 +39,7 @@
 	int		(*close)(struct pstore_info *psi);
 	ssize_t		(*read)(u64 *id, enum pstore_type_id *type,
 			struct timespec *time, struct pstore_info *psi);
-	u64		(*write)(enum pstore_type_id type, int part,
+	u64		(*write)(enum pstore_type_id type, unsigned int part,
 			size_t size, struct pstore_info *psi);
 	int		(*erase)(enum pstore_type_id type, u64 id,
 			struct pstore_info *psi);