KVM: VMX: Drop caching of KVM's desired sec exec controls for vmcs01

Remove the secondary execution controls cache now that it's effectively
dead code; it is only read immediately after it is written.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210810171952.2758100-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>