KVM: x86: Clear "has_error_code", not "error_code", for RM exception injection

KVM: x86: Clear "has_error_code", not "error_code", for RM exception injection

When injecting an exception into a vCPU in Real Mode, suppress the error
code by clearing the flag that tracks whether the error code is valid, not
by clearing the error code itself.  The "typo" was introduced by recent
fix for SVM's funky Paged Real Mode.

Opportunistically hoist the logic above the tracepoint so that the trace
is coherent with respect to what is actually injected (this was also the
behavior prior to the buggy commit).

Fixes: b97f07458373 ("KVM: x86: determine if an exception has an error code only when injecting it.")
Cc: stable@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20230322143300.2209476-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>