Bluetooth: Fix sk_sndtimeo initialization for L2CAP socket

sk_sndtime value should be specified in jiffies thus initial value
needs to be converted from miliseconds. Otherwise this timeout is
unreliable when CONFIG_HZ is not set to 1000.

Signed-off-by: Andrzej Kaczmarek <andrzej.kaczmarek@tieto.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>