With code elsewhere doing something conditional on whether or not
context tracking is enabled, we want a stub function that tells us
context tracking is not enabled, when CONFIG_CONTEXT_TRACKING is
not set.
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Will deacon <will.deacon@arm.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>