f2fs: fix remove page failed in invalidate compress pages

Since compress inode not a regular file, generic_error_remove_page in
f2fs_invalidate_compress_pages will always be failed, set compress
inode as a regular file to fix it.

Fixes: 6ce19aff ("f2fs: compress: add compress_inode to cache compressed blocks")
Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>