f2fs: fix to avoid forcing direct write to use buffered IO on inline_data inode

f2fs: fix to avoid forcing direct write to use buffered IO on inline_data inode

Jinsu Lee reported a performance regression issue, after commit
5c8764f8679e ("f2fs: fix to force buffered IO on inline_data
inode"), we forced direct write to use buffered IO on inline_data
inode, it will cause performace regression due to memory copy
and data flush.

It's fine to not force direct write to use buffered IO, as it
can convert inline inode before committing direct write IO.

Fixes: 5c8764f8679e ("f2fs: fix to force buffered IO on inline_data inode")
Reported-by: Jinsu Lee <jinsu1.lee@samsung.com>
Closes: https://lore.kernel.org/linux-f2fs-devel/af03dd2c-e361-4f80-b2fd-39440766cf6e@kernel.org
Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>