dev: -Wdeprecated-copy not available on all supported compilers

dev: -Wdeprecated-copy not available on all supported compilers

This option has been introduced in:
1) gcc/9.0 [1]
2) clang/10.0.0 [2]

[1]: https://gcc.gnu.org/gcc-9/changes.html
[2]: https://releases.llvm.org/10.0.0/tools/clang/docs/ReleaseNotes.html

Change-Id: Iee9de40ca462107ec78603ffe5bc0891d6904730
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/37795
Reviewed-by: Richard Cooper <richard.cooper@arm.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Gabe Black <gabe.black@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>