We only have one GDBState which should be allocated at the time we
process any commands. This will make further clean-up a bit easier.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Damien Hedde <damien.hedde@greensocs.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Message-Id: <20200316172155.971-8-alex.bennee@linaro.org>