f2fs: compress: remove unneeded f2fs_put_dnode()

If we don't initialize dn.inode_page for f2fs_get_block(),
f2fs_get_block() will call f2fs_put_dnode() itself, so let's
remove unneeded f2fs_put_dnode() in f2fs_vm_page_mkwrite().
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/file.c

@@ -117,7 +117,6 @@ static vm_fault_t f2fs_vm_page_mkwrite(struct vm_fault *vmf)
 		f2fs_do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, true);
 		set_new_dnode(&dn, inode, NULL, NULL, 0);
 		err = f2fs_get_block(&dn, page->index);
-		f2fs_put_dnode(&dn);
 		f2fs_do_map_lock(sbi, F2FS_GET_BLOCK_PRE_AIO, false);
 	}