Fs_mgr: Fix format code

Suggested printing for off_t is to cast to intmax_t and print that.

Follow-up to https://android-review.googlesource.com/133111.

Change-Id: Icff6844044c3d0fa6372c3f399453a526fd89954

fs_mgr/fs_mgr_verity.c

@@ -431,7 +431,7 @@ static int check_verity_restart(const char *fname)
     }
 
     if (lseek(fd, s.st_size - size, SEEK_SET) == -1) {
-        ERROR("Failed to lseek %zu %s (%s)\n", s.st_size - size, fname,
+        ERROR("Failed to lseek %jd %s (%s)\n", (intmax_t)(s.st_size - size), fname,
             strerror(errno));
         goto out;
     }