KVM: SVM: Explicitly check max SEV ASID during sev_hardware_setup()

Query max_sev_asid directly after setting it instead of bouncing through
its wrapper, svm_sev_enabled().  Using the wrapper is unnecessary
obfuscation.

No functional change intended.

Reviewed by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422021125.3417167-12-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>