KVM: x86: Do not use kvm_rip_read() unconditionally in KVM tracepoints

Not all VMs allow access to RIP.  Check guest_state_protected before
calling kvm_rip_read().

This avoids, for example, hitting WARN_ON_ONCE in vt_cache_reg() for
TDX VMs.

Fixes: 81bf912b ("KVM: TDX: Implement TDX vcpu enter/exit path")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Message-ID: <20250415104821.247234-2-adrian.hunter@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>