Fix gcc -O1 builds for ARM

The builds are failing as GCC somehow thinks ino might be
uninitialized before use.

Change-Id: Id99fd5e46bcbaafd5001752e16c3f77c1d568556

minix/lib/libsffs/lookup.c

@@ -107,7 +107,7 @@ int do_lookup(ino_t dir_nr, char *name, struct fsdriver_node *node,
 {
 /* Resolve a path string to an inode.
  */
-  struct inode *dir_ino, *ino;
+  struct inode *dir_ino, *ino = NULL;
   struct sffs_attr attr;
   char path[PATH_MAX];
   int r;