i386/cpu: Move adjustment of CPUID_EXT_PDCM before feature_dependencies[] check

i386/cpu: Move adjustment of CPUID_EXT_PDCM before feature_dependencies[] check

There is one entry relates to CPUID_EXT_PDCM in feature_dependencies[].
So it needs to get correct value of CPUID_EXT_PDCM before using
feature_dependencies[] to apply dependencies.

Besides, it also ensures CPUID_EXT_PDCM value is tracked in
env->features[FEAT_1_ECX].

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250304052450.465445-2-xiaoyao.li@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>