Bluetooth: Handle pairing cancel req for LE device

When pairing is cancelled during the pass key request UI pop
up, call pairing complete after sending SMP_CMD_PAIRING_FAIL
which would clean up all the pairing callbacks and send
notification to the above layers.

Change-Id: I0d3e9bdc19dc2fcae280d3c70ddea976ecb218c7
Signed-off-by: Archana Ramachandran <archanar@codeaurora.org>
CRs-fixed: 430016
Signed-off-by: Sunny Kapdi <sunnyk@codeaurora.org>
Signed-off-by: Mallikarjuna GB <gbmalli@codeaurora.org>