Bluetooth: __l2cap_wait_ack() use msecs_to_jiffies()

Use msecs_to_jiffies() instead of using HZ so that it
is easier to specify the time in milliseconds.

Also add a #define L2CAP_WAIT_ACK_POLL_PERIOD to specify the 200ms
polling period so that it is defined in a single place.

Signed-off-by: Dean Jenkins <Dean_Jenkins@mentor.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>