f2fs: fix to clear FI_NO_PREALLOC

[ Upstream commit 28cfafb73853f0494b06649716687a3ea07681d5 ]

We need to clear FI_NO_PREALLOC flag in error path of f2fs_file_write_iter,
otherwise we will lose the chance to preallocate blocks in latter write()
at one time.

Fixes: dc91de78 ("f2fs: do not preallocate blocks which has wrong buffer")
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>