perf map_groups: Pass the object to map_groups__find_ams()

We were just passing a map to look for and reuse its map->groups member,
but the idea is that this is going away, as a map can be in multiple
rb_trees when being reused via a map_node, so do as all the other
map_groups methods and pass as its first arg the object being operated
on.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-nmi2pbggqloogwl6vxrvex5a@git.kernel.org


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