Fix typo with NVStore

[ccli8]

Description

I believe the below code is a typo:

mbed-os/features/nvstore/source/nvstore.cpp:

memcpy(_flash_area_params, 0, sizeof(_flash_area_params));

And I fix as below:

memset(_flash_area_params, 0, sizeof(_flash_area_params));

Because _flash_area_params will be re-initialized later, the typo won't cause trouble on most targets. But it will on NUMAKER_PFM_M2351 port of which is on-going. NUMAKER_PFM_M2351 is Cortex-M23 based and has TrustZone support. Read flash address 0 is not always legal because flash is partitioned into secure/non-secure.

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

[davidsaada]

This line was actually removed in this PR, waiting to be merged. Reason is, as you also noticed, that this structure is initialized at init phase. I don't mind approving this PR, until my PR is merged, if it helps fixing an immediate issue.

[0xc0170]

@davidsaada Should this be integrated first as bugfix, thus would be part of the next patch release. And your PR would be for the next minor as adding new API?

[davidsaada]

Should this be integrated first as bugfix, thus would be part of the next patch release. And your PR would be for the next minor as adding new API?

Yes, I believe it's the right thing to do.

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 1720
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/6595/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 1356
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/6595/

[mbed-ci]

Test : SUCCESS

Build number : 1520
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/6595/1520

[adbridge]

This line did not even come into the code base until #6388 which is marked for 5.9 so not sure this should be patched !