msdos_file.c: Reverse return codes per Gedare

cpukit/libfs/src/dosfs/msdos_file.c

@@ -244,8 +244,8 @@ msdos_file_sync(rtems_libio_t *iop)
     rc = fat_sync(&fs_info->fat);
 
     rtems_semaphore_release(fs_info->vol_sema);
-    if ( rc == 0 )
-      return RC_OK;
+    if ( rc != 0 )
+      rtems_set_errno_and_return_minus_one(EIO);
 
-    rtems_set_errno_and_return_minus_one(EIO);
+    return RC_OK;
 }