rasdaemon: Fix mem_fail_event build breakage

Commit 566a526 ("add mem_fail_event trigger") introduces an event
trigger for a memory failure event.

However, if the rasdaemon is not configured with enable-memory-failure,
the setup function of the trigger, mem_fail_event_trigger_setup(), will
result in an undefined reference linker error when called through
setup_event_trigger().

Ensure that the setup function for the trigger is called only when the
rasdaemon has been configured with enable-memory-failure.

Fixes: 566a526 ("add mem_fail_event trigger")
Signed-off-by: Avadhut Naik <avadhut.naik@amd.com>

ras-events.c

@@ -55,7 +55,9 @@ char *choices_disable;
 
 static const struct event_trigger event_triggers[] = {
 	{ "mc_event", &mc_event_trigger_setup },
+#ifdef HAVE_MEMORY_FAILURE
 	{ "memory_failure_event", &mem_fail_event_trigger_setup },
+#endif
 };
 
 static int get_debugfs_dir(char *tracing_dir, size_t len)