Change Mbed TLS platform error code and value

[RonEld]

Description

Change error from MBEDTLS_PLATFORM_HW_FAILED to
MBEDTLS_PLATFORM_HW_ACCEL_FAILED and the value to 0x70,
as the previous value cannot be used as a low level error code.
resolves #8433

Pull request type

[x ] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Docs update
[ ] Test update
[ ] Breaking change

[RonEld]

@cmonr Thank for the review. Do you think it's better to remove MBEDTLS_ERR_PLATFORM_HW_FAILED altogether to avoid any misuse? Note it was added only for 5.10.0

[cmonr]

@RonEld I would suggest leaving it in for now, since any code state removals could be seen as a breaking change and move the PR out to 5.11.

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3360
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8434/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2995
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8434/

[mbed-ci]

Test : SUCCESS

Build number : 3165
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8434/3165