i386: Add -noTSX aliases for hle=off, rtm=off CPU models

We have been trying to avoid adding new aliases for CPU model
versions, but in the case of changes in defaults introduced by
the TAA mitigation patches, the aliases might help avoid user
confusion when applying host software updates.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>