BaseTools/tools_def GCC5: disable LTO for ASLC invocations

BaseTools/tools_def GCC5: disable LTO for ASLC invocations

GCC for 32-bit ARM chokes on .aslc files when running with LTO
enabled. Since LTO has no benefit whatsoever here, just disable
it globally for GCC5 and up when building .aslc files.

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: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>