Clean up include paths.

[tkem]

Description

When studying the mbed source code, I noticed #includes usually refer to files in other directories using double-quoted paths relative to the repository root ("platform/platform.h", "hal/gpio_api.h", etc.).
There are a few files where this is not the case, apparently relying on includes path implicitly set by the build environment. So this is not a real issue (until you change the build environment, of course), but simply something I'd suggest for consistency...

Pull request type

Nothing's broken (for now), so I think "Refactor" describes this best (you may want to add "Code Cleanup" as an option some day).

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

[deepikabhavnani]

Thanks for cleanup. Looks good to me 👍

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 3096
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7903/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2705
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7903/

[mbed-ci]

Test : SUCCESS

Build number : 2885
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7903/2885

[cmonr]

/morph mbed2-build