BaseTools AARCH64: use tiny code model by default
BaseTools AARCH64: use tiny code model by default

The AARCH64 tiny code model produces more efficient code, since it
uses relative symbol references rather than absolute references, i.e.,
an emitted relative reference refers to the symbol directly rather
than a literal containing its 64-bit absolute address. This saves
space in the binary, and reduces the number of relocation fixups that
need to be applied by the PE/COFF loader.

So now that we support relative relocations in GenFw, move to the
tiny code model by default. Note that the large model can still be
selected by individual modules by adding -mcmodel=large to the
appropriate CC_FLAGS.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Tested-by: Leif Lindholm <leif.lindholm@linaro.org>

git-svn-id: 3158a46dfd52e07d1fda3e32e1ab2e353a00b20f@18242 6f19259b-4bc3-4df7-8a09-765794883524

MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2,MattDevo/edk2