Tools: Drop quotes from makefiles

[theotherjimmy]

Description

This is a pretty simple bug: including ' characters in the commands
within a Makefile can sometimes cause problems with certain shell
configurations on Windows. This PR removes the 's, as they are not
needed.

Pull request type

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

[deepikabhavnani]

👍 Linking works now with Makefile

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 2598
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/7503/

Triggering tests

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

[mbed-ci]

Exporter Build : SUCCESS

Build number : 2242
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/7503/

[mbed-ci]

Test : SUCCESS

Build number : 2351
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/7503/2351