target/arm/hvf: Include missing 'cpu-qom.h' header

target/arm/hvf: Include missing 'cpu-qom.h' header

ARMCPU typedef is declared in "cpu-qom.h". Include it in
order to avoid when refactoring unrelated headers:

  target/arm/hvf_arm.h:23:41: error: unknown type name 'ARMCPU'
     23 | void hvf_arm_set_cpu_features_from_host(ARMCPU *cpu);
        |                                         ^

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-id: 20250513173928.77376-10-philmd@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>