ArmVirtPkg/PrePi: don't export PE/COFF and LZMA libraries via HOBs

ArmVirtPkg/PrePi: don't export PE/COFF and LZMA libraries via HOBs

The PrePi code we inherited from ArmPlatformPkg contains a rather
obscure optimization, where entry points of the PE/COFF and LZMA
handling routines are recorded in special HOBs, allowing DXE core
to call into that code directly rather than carry its own copy of
these libraries.

Given that no ArmVirtPkg platforms actually include the library
resolutions* that take advantage of these optimizations, let's not
bother with them, and remove the associated code.

* EmbeddedPkg/Library/LzmaHobCustomDecompressLib/LzmaHobCustomDecompressLib.inf
  EmbeddedPkg/Library/DxeHobPeCoffLib/DxeHobPeCoffLib.inf

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Laszlo Ersek <lersek@redhat.com>