staging: erofs: return the error value if fill_inline_data() fails

We should consider the error returned by fill_inline_data() when filling
last page in fill_inode(). If not getting inode will be successful even
though last page is bad. That is illogical. Also change -EAGAIN to 0 in
fill_inline_data() to stand for successful filling.

Signed-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Gao Xiang <gaoxiang25@huawei.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>