target/i386: Add SERIALIZE cpu feature

target/i386: Add SERIALIZE cpu feature

The availability of the SERIALIZATION instruction is indicated
by the presence of the CPUID feature flag SERIALIZE, which is
defined as CPUID.(EAX=7,ECX=0):ECX[bit 14].

The release spec link is as follows:
https://software.intel.com/content/dam/develop/public/us/en/documents/\
architecture-instruction-set-extensions-programming-reference.pdf

The associated kvm patch link is as follows:
https://lore.kernel.org/patchwork/patch/1268025/

Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Message-Id: <1593991036-12183-2-git-send-email-cathy.zhang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>