Bluetooth: Fix incorrect clearing of SMP_FLAG_INITIATOR

Bluetooth: Fix incorrect clearing of SMP_FLAG_INITIATOR

When the SMP context is created all flags default to zero. To determine
that we are the initiators it's therefore best to simply change the flag
value when we know we're sending the first SMP PDU. Clearing the flag
when receiving a Pairing Request is not correct since the request may be
a response to a previous Security Request from us (for which we would
already have correctly set the flag). Same goes for receiving a Security
Request which may be coming after us already starting pairing by sending
a Pairing Request.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>