perf machine: Simplify accessing the host machine

It is always there, no sense in calling a function named
"perf_session__find_host_machine".

Also no sense in checking if that function return is NULL, so ditch
needless error handling.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-a6a3zx3afbrxo8p2zqm5mxo8@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/session.c

@@ -821,7 +821,7 @@ static struct machine *
 		return perf_session__findnew_machine(session, pid);
 	}
 
-	return perf_session__find_host_machine(session);
+	return &session->machines.host;
 }
 
 static int perf_session_deliver_event(struct perf_session *session,

tools/perf/util/session.h

@@ -74,12 +74,6 @@ int perf_session__create_kernel_maps(struct perf_session *self);
 void perf_session__set_id_hdr_size(struct perf_session *session);
 void perf_session__remove_thread(struct perf_session *self, struct thread *th);
 
-static inline
-struct machine *perf_session__find_host_machine(struct perf_session *self)
-{
-	return &self->machines.host;
-}
-
 static inline
 struct machine *perf_session__find_machine(struct perf_session *self, pid_t pid)
 {