Fix warning messages in remove symbolic

inode_dec_link_count has included drop_nlink/ mark_inode_dirty

Author: RoyWFHuang

inode.c

@@ -654,8 +654,6 @@ static int simplefs_unlink(struct inode *dir, struct dentry *dentry)
 #endif
 
     inode_dec_link_count(inode);
-    drop_nlink(inode);
-    mark_inode_dirty(inode);
 
     /* Free inode and index block from bitmap */
     if (S_ISLNK(inode->i_mode))