[patch] Switch to text mode during efi boot

The attached patch causes both boot1 and loader.efi to switch to text
mode. This only
seems to make a difference on Macs where otherwise no information was being
displayed.

The ConsoleControl.h file is copied from
EdkCompatibilityPkg/Foundation/Protocol/ConsoleControl in
https://github.com/tianocore/edk2.

I tested that both programs are able to change to text mode by
enabling only one of them at a time.

With this patch I am able to see loaders output on all the macs I
tried. The kernel boots correctly on a MacPro, but unfortunately it
doesn't seem to be able to find the efi buffer in a MacBookPro.

Some design questions:

* Why do we have both boot1 and loader? It is just the issue with
building a usb image without root that requires having a boot1 that
has a predictable size?

* Even if we want to keep both boot1 and loader, could boot1 use libefi?

* Is it ok to always switch to text mode in libefi or should it
provide a switch_to_text_mode function?

Cheers,
Rafael