perf tools: Set thread->mg.machine in all places

We were setting this only in machine__init(), i.e. for the map_groups that
holds the kernel module maps, not for the one used for a thread's executable
mmaps.

Now we are sure that we can obtain the machine where a thread is by going
via thread->mg->machine, thus we can, in the following patch, make all
codepaths that receive machine _and_ thread, drop the machine one.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
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-y6zgaqsvhrf04v57u15e4ybm@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>