Support erase value in Flash HAL drivers, FlashIAP and block devices

[davidsaada]

Description

This change adds support for getting the flash erase value in HAL drivers (all), FlashIAP driver and FlashIAP block device. It is required for the case upper layers need to check whether a flash area is erased or not. The vast majority of flash components produce the all ones (0xFF) value following an erase, and this includes all components currently supported by mbed-os. However, this change allows the addition of other components with different erase values (such as 0).
Resolves #6405.

Pull request type

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

[0xc0170]

cc @ARMmbed/team-st-mcd @ARMmbed/team-silabs @ARMmbed/team-nxp @ARMmbed/team-realtek @ARMmbed/team-renesas @ARMmbed/team-toshiba

[0xc0170]

/morph build

[mbed-ci]

Build : FAILURE

Build number : 3551
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8589/

[0xc0170]

@davidsaada Some build failures indicate missing flash HAL implementations, please review

[davidsaada]

Some build failures indicate missing flash HAL implementations, please review

Thanks @0xc0170. Should be OK now.

[0xc0170]

/morph build

[mbed-ci]

Build : FAILURE

Build number : 3559
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8589/

[davidsaada]

Should really be OK now.

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3570
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/8589/

Triggering tests

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

[mbed-ci]

Exporter Build : FAILURE

Build number : 3179
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8589/

[mbed-ci]

Test : SUCCESS

Build number : 3350
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/8589/3350

[cmonr]

Note: This PR is now a part of a rollup PR (#8675).

Jenkins CI export nodes experienced many drops throughout the day causing false failures. In an attempt to get those PRs through CI, while keeping CI load low, several PRs have been bundled into a single rollup PR.

If any more commits are made in this PR, this PR will remain open and have to go through CI on its own.

[0xc0170]

/morph export-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 3191
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/8589/

[deepikabhavnani]

flash_get_erase_value is added her as non-secure entry function. May I know why this API is different than rest of the API's in file?

It is causing build failures in generating secure side library :-(

[deepikabhavnani]

CC @ARMmbed/mbed-os-maintainers @ARMmbed/team-nuvoton