target/i386: define a new MSR based feature word - FEAT_CORE_CAPABILITY

target/i386: define a new MSR based feature word - FEAT_CORE_CAPABILITY

MSR IA32_CORE_CAPABILITY is a feature-enumerating MSR, which only
enumerates the feature split lock detection (via bit 5) by now.

The existence of MSR IA32_CORE_CAPABILITY is enumerated by CPUID.7_0:EDX[30].

The latest kernel patches about them can be found here:
https://lkml.org/lkml/2019/4/24/1909

Signed-off-by: Xiaoyao Li <xiaoyao.li@linux.intel.com>
Message-Id: <20190617153654.916-1-xiaoyao.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>