BLE: store secure connections ltk in both local and peer entry

[paul-szczepanek-arm]

Description

Secure connections LTK was being stored only in the peer entry which meant the remote encryption request wouldn't find the correct key. This fix stores the key in both entries.

Pull request type

[X] Fix
[ ] Refactor
[ ] New target
[ ] Feature
[ ] Breaking change

[pan-]

Please backport the other fixes.

[paul-szczepanek-arm]

will do:
#7687
#7688

[cmonr]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2795
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7681/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build
/morph mbed2-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2425
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7681/

[cmonr]

/morph test

[mbed-ci]

Test : FAILURE

Build number : 2535
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7681/2535

[adbridge]

Looks like this has failed due to some networking issues in CI. Suggest we re-run this once the CI is less heavily loaded.

[cmonr]

/morph test

[mbed-ci]

Test : FAILURE

Build number : 2561
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7681/2561

[cmonr]

/morph test

[mbed-ci]

Test : FAILURE

Build number : 2570
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7681/2570

[cmonr]

Well then. Neither of those test failures appear to be caused by the PR, and we've been seeing them all week.

/morph test

[mbed-ci]

Test : SUCCESS

Build number : 2579
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7681/2579