OvmfPkg/BhyvePkg: honor FwCfg when setting the bootorder

[ckoehne]

Bhyve has added support for the bootorder FwCfg file some time ago [1][2]. This FwCfg file is currently ignored by the OVMF and has no effect. Copy the relevant code from Qemu to Bhyve to make it usable.

[1] https://github.com/freebsd/freebsd-src/commit/6632a0a4e3ab68b0e31b612e8aeca14de3fc8159 [2] https://github.com/freebsd/freebsd-src/commit/480bef9481f0c44b19ac4b2adb09f6c3191acd41

[bcran]

@ckoehne It looks like this branch is outdated wrt master now - could you rebase it please? Apparently it can't be done automatically:

Mergify needs the author permission to update the base branch of the pull request. https://github.com/Beckhoff needs to authorize modification on its head branch.

[bcran]

@mergifyio rebase

[mergify[bot]]

rebase

❌ Unable to rebase: user bcran is unknown.

Please make sure `bcran` has logged in Mergify dashboard.

[bcran]

@Mergifyio rebase

[mergify[bot]]

rebase

❌ Pull request can't be updated with latest base branch changes

Mergify needs the author permission to update the base branch of the pull request. @Beckhoff needs to [authorize modification on its head branch](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/allowing-changes-to-a-pull-request-branch-created-from-a-fork).

[bcran]

@ckoehne Could you edit this PR to "allow edits by maintainers" please? Mergify is refusing to merge it without that setting enabled.

[ckoehne]

@bcran I can't see any button to enable "allow edits by maintainers". Maybe because I'm not the owner of our fork?

[ckoehne]

@bcran I've created a new PR from my personal fork and enabled "allow edits by maintainers": https://github.com/tianocore/edk2/pull/5790