add config option for phy media interface

[JojoS62]

Summary of changes

This PR extends #12464
by the option for the hardware phy connection. The default is set to RMII and could not be changed for custom targets. This PR adds an option to select RMII or MII interface (probably others, but not tested).

Impact of changes

This option does not change compatibility and has no impact on generated code when using default.
For using the MII interface, the custom init code has to be changed. This code is placed in stm32xx_eth_init.c and is target dependent and can be placed in a custom target extension.

Migration actions required

Documentation

This PR uses the standard Mbed configuration via mbed_app.json.

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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

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

Applies to custom targets that use different than RMII phy hardware connection.
The modification was tested on custom hardware with DP83848 phy and STM32F407VG MCU.

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Reviewers

@jeromecoutant

[ciarmcom]

@JojoS62, thank you for your changes.
@jeromecoutant @ARMmbed/mbed-os-ipcore @ARMmbed/mbed-os-maintainers please review.

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CI started

[mbed-ci]

Test run: FAILED

Summary: 1 of 6 test jobs failed
Build number : 1
Build artifacts

Failed test jobs:

• jenkins-ci/mbed-os-ci_greentea-test

[JojoS62]

it looks like there were problems with memory size, but not related to this PR. The failing test is about F303 which has no Ethernet.

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Will restart tests later today

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CI started

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CI restarted

[mbed-ci]

Test run: SUCCESS

Summary: 6 of 6 test jobs passed
Build number : 3
Build artifacts