Promote this function from aarch64 to fully general use.
Use it to unify the code sequences for generating illegal
opcode exceptions.
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>
Reviewed-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Message-id: 20190807045335.1361-11-richard.henderson@linaro.org
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>