some improvement on FoE (large mailboxes, busy answer, firmware_update)

[ghost]

No description provided.

[mheden]

CLA received.

[mheden]

Sorry for the delay, I'll look over this as soon as my schedule permits.

[nakarlsson]

Keep EC_MAXFOEDATA and set it to EC_MAXMBX

[nakarlsson]

We'll commit the change in ethercatfoe with my comment, the changes in firmware we'll leave out.

[gralpli]

This pull request solves a problem for me! Why hasn’t this been accepted yet?

firm_update.c from the master branch always failed with status code -3. Wireshark revealed that the FoE response from the slave contained gibberish. (aFOEp->MbxHeader.mbxtype & 0x0f) evaluated to 0x0a.

I will investigate further what the actual problem was and why this pull request solved it.

[nakarlsson]

Some minor updates of the PR for FoE, and I think the update of fimrware update should be handled in a seperate PR. Perhaps you can finish the started work?

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.

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