target/arm/cpu: flags2 is always uint64_t

target/arm/cpu: flags2 is always uint64_t

Do not rely on target dependent type, but use a fixed type instead.
Since the original type is unsigned, it is safe to extend its size
without any side effect.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20250325045915.994760-21-pierrick.bouvier@linaro.org>