target/i386: Add VNMI and automatic IBRS feature bits

target/i386: Add VNMI and automatic IBRS feature bits

Add the following featute bits.

vnmi: Virtual NMI (VNMI) allows the hypervisor to inject the NMI into the
      guest without using Event Injection mechanism meaning not required to
      track the guest NMI and intercepting the IRET.
      The presence of this feature is indicated via the CPUID function
      0x8000000A_EDX[25].

automatic-ibrs :
      The AMD Zen4 core supports a new feature called Automatic IBRS.
      It is a "set-and-forget" feature that means that, unlike e.g.,
      s/w-toggled SPEC_CTRL.IBRS, h/w manages its IBRS mitigation
      resources automatically across CPL transitions.
      The presence of this feature is indicated via the CPUID function
      0x80000021_EAX[8].

The documention for the features are available in the links below.
a. Processor Programming Reference (PPR) for AMD Family 19h Model 01h,
   Revision B1 Processors
b. AMD64 Architecture Programmer’s Manual Volumes 1–5 Publication No. Revision
   40332 4.05 Date October 2022

Signed-off-by: Santosh Shukla <santosh.shukla@amd.com>
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Babu Moger <babu.moger@amd.com>
Link: https://www.amd.com/system/files/TechDocs/55898_B1_pub_0.50.zip
Link: https://www.amd.com/system/files/TechDocs/40332_4.05.pdf
Message-Id: <20230504205313.225073-7-babu.moger@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>