Update Mbed TLS to version 2.13.0

[simonbutcher]

Description

This PR updates Mbed TLS to the latest release, 2.13.0.

This PR supersedes PR #7940 which unfortunately I can't update, so have had to provide a new PR. #7940 can now be closed.

Note, this PR is title/tagged 'DO NOT MERGE' whilst formal release approval is pending.

PR should be reviewed by @RonEld and/or @Patater where available.

Pull request type

[ ] Fix
[ ] Refactor
[ ] Target update
[X] Functionality change
[ ] Breaking change

[Patater]

LGTM

I've verified the mbedtls code is identical to that in #7940, except that the version information has been updated.

[adbridge]

/morph build

[adbridge]

Not to be merged until release approval has been obtained by the TLS team and communicated to us

[mbed-ci]

Build : FAILURE

Build number : 2999
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7974/

[simonbutcher]

I'm pleased to say this version has been approved for release, so the 'DO NOT MERGE' label can be removed.

[cmonr]

/morph build

Yay, a new CI issue. The node failued to report the build success...

[mbed-ci]

Build : SUCCESS

Build number : 3000
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7974/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2610
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7974/

[mbed-ci]

Test : SUCCESS

Build number : 2763
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7974/2763

[juhoeskeli]

Does not link succesfully with ARMCC & IAR: x509.c@907,0: #223-D: function "gmtime_r" declared implicitly

[juhoeskeli]

Tested with armcc 5.06

[RonEld]

@juhoeskeli This issue is opened in Mbed-TLS/mbedtls#1907
I believe a workaropund should be to disable MBEDTLS_HAVE_TIME_DATE