KVM: x86: Drop @invalidate_gpa param from kvm_x86_ops' tlb_flush()

Drop @invalidate_gpa from ->tlb_flush() and kvm_vcpu_flush_tlb() now
that all callers pass %true for said param, or ignore the param (SVM has
an internal call to svm_flush_tlb() in svm_flush_tlb_guest that somewhat
arbitrarily passes %false).

Remove __vmx_flush_tlb() as it is no longer used.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200320212833.3507-17-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>