Add QSPI and relevant test support for target EP_AGORA

[trowbridgec]

Summary of changes

This PR adds support (and relevant tests) for QSPI on the EP_AGORA target. As part of adding the Greentea test support, I have added a new flash config file for the Winbond W25Q32JV 32Mbit NOR flash chip (which is the flash chip on the EP_AGORA target).

Impact of changes

Migration actions required

Documentation

None

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Pull request type

[x] Patch update (Bug fix / Target update / Docs update / Test update / Refactor)
[] Feature update (New feature / Functionality change / New API)
[] Major update (Breaking change E.g. Return code change / API behaviour change)

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Test results

[] No Tests required for this change (E.g docs only update)
[x] Covered by existing mbed-os tests (Greentea or Unittest)
[] Tests / results supplied as part of this PR

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Reviewers

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[trowbridgec]

@ARMmbed/team-embeddedplanet @maclobdell

[ciarmcom]

@trowbridgec, thank you for your changes.
@ARMmbed/mbed-os-maintainers @ARMmbed/mbed-os-hal @ARMmbed/mbed-os-test please review.

[0xc0170]

CI started

[mbed-ci]

Test run: SUCCESS

Summary: 11 of 11 test jobs passed
Build number : 1
Build artifacts