Skip flushing file if lfs_file_rawseek() doesn't change position

lfs.c

@@ -3048,14 +3048,6 @@ relocate:
 
 static lfs_soff_t lfs_file_rawseek(lfs_t *lfs, lfs_file_t *file,
         lfs_soff_t off, int whence) {
-#ifndef LFS_READONLY
-    // write out everything beforehand, may be noop if rdonly
-    int err = lfs_file_flush(lfs, file);
-    if (err) {
-        return err;
-    }
-#endif
-
     // find new pos
     lfs_off_t npos = file->pos;
     if (whence == LFS_SEEK_SET) {
@@ -3071,6 +3063,19 @@ static lfs_soff_t lfs_file_rawseek(lfs_t *lfs, lfs_file_t *file,
         return LFS_ERR_INVAL;
     }
 
+    if (file->pos == npos) {
+        // noop - position has not changed
+        return npos;
+    }
+
+#ifndef LFS_READONLY
+    // write out everything beforehand, may be noop if rdonly
+    int err = lfs_file_flush(lfs, file);
+    if (err) {
+        return err;
+    }
+#endif
+
     // update pos
     file->pos = npos;
     return npos;