OvmfPkg/BhyvePkg: honor FwCfg when setting the bootorder

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

Signed-off-by: Corvin Köhne <c.koehne@beckhoff.com>
3 files changed