f2fs: compress: change the first parameter of page_array_{alloc,free} to sbi

No logic changes, just cleanup and prepare for fixing the UAF issue
in f2fs_free_dic.

Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Signed-off-by: Baocong Liu <baocong.liu@unisoc.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>