target/i386: Introduce SierraForest-v2 model

target/i386: Introduce SierraForest-v2 model

Update SierraForest CPU model to add LAM, 4 bits indicating certain bits
of IA32_SPEC_CTR are supported(intel-psfd, ipred-ctrl, rrsba-ctrl,
bhi-ctrl) and the missing features(ss, tsc-adjust, cldemote, movdiri,
movdir64b)

Also add GDS-NO and RFDS-NO to indicate the related vulnerabilities are
mitigated in stepping 3.

Tested-by: Xuelian Guo <xuelian.guo@intel.com>
Signed-off-by: Tao Su <tao1.su@linux.intel.com>
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250121020650.1899618-2-tao1.su@linux.intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>