No any behavior to variable occupied in z_erofs_attach_page() which
is only caller to z_erofs_pagevec_enqueue().

Link: https://lore.kernel.org/r/20210419102623.2015-1-zbestahu@gmail.comSigned-off-by: Yue Hu <huyue2@yulong.com>
Reviewed-by: Gao Xiang <xiang@kernel.org>
Signed-off-by: Gao Xiang <xiang@kernel.org>