gdbstub: Prefer cached CpuClass over CPU_GET_CLASS() macro

CpuState caches its CPUClass since commit 6fbdff87062
("cpu: cache CPUClass in CPUState for hot code paths"),
use it.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250122093028.52416-9-philmd@linaro.org>
4 files changed