BaseTools/Conf/tools_def.template: drop ARM/AARCH support from GCC46/GCC47

BaseTools/Conf/tools_def.template: drop ARM/AARCH support from GCC46/GCC47

This drops ARM and AARCH64 support from the GCC46 and GCC47 toolchain
definitions, which are on the list to be removed, along with VS2003,
VS2005, VS2008, VS2010, DDK3790, UNIXGCC, GCC44, GCC45, ELFGCC, CYGGCC,
ICC, ICC11 and MYTOOLS.

Since GCC46 and GCC47 are the only ones on that list that support ARM
and/or AARCH64, let's give Liming a hand and cover the ARM side of
things first, so that everything that remains to be removed is x86
only.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1377
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Liming Gao <liming.gao@intel.com>
[lersek@redhat.com: add bugzilla reference and CCs]
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>