Update SO_ATTACH_FILTER usage for sock_setsockopt in Linux Kernels 5.9+

[landhb]

In Linux 5.9+, the sock_setsockopt() method now takes a sockptr_t as an argument.

int sock_setsockopt(struct socket *sock, int level, int op, sockptr_t optval, unsigned int optlen);

Vs in 5.8:

int sock_setsockopt(struct socket *sock, int level, int op, char __user *optval, unsigned int optlen);