Fix data aligment problem at STM32F4 hash write

[KariHaapalehto]

Description

Fix data aligment error what were seen with ARM compiler and release profile.
The fix has been tested with GCC_ARM, ARM and IAR compilers using both release and debug profiles. No regression were seen.

Pull request type

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

[jeromecoutant]

ST_INTERNAL_REF 48706

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2313
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7176/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 1936
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7176/

[mbed-ci]

Test : SUCCESS

Build number : 2092
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7176/2092

[jeromecoutant]

Hi @KariHaapalehto

Fix data aligment error what were seen with ARM compiler and release profile.

ST driver team would need more details about error you have seen.
Is it some test error, compilation error ?
Thx

[KariHaapalehto]

This is not test nor compiler error.
The error is in code, which just came up with arm compiler and release profile