Remove some more Qemu/Xen stuff

We don't need that on real hardware, and we can still look it up
for reference in OvmfPkg if necessary

Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>
corebootPkg: Remove more libraries

Those are only used by Ovmf code that we directly import from
over there, using Ovmf libraries in the process.

Signed-off-by: Patrick Georgi <patrick@georgi-clan.de>