bluetooth: sco: Fix sockptr reference.

net/bluetooth/sco.c: In function ‘sco_sock_setsockopt’:
net/bluetooth/sco.c:862:3: error: cannot convert to a pointer type
  862 |   if (get_user(opt, (u32 __user *)optval)) {
      |   ^~

Signed-off-by: David S. Miller <davem@davemloft.net>