perf trace: Look up maps just on the __augmented_syscalls__ BPF object

perf trace: Look up maps just on the __augmented_syscalls__ BPF object

We can conceivably have multiple BPF object files for other purposes, so
better look just on the BPF object containing the __augmented_syscalls__
map for all things augmented_syscalls related.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Luis Cláudio Gonçalves <lclaudio@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-3jt8knkuae9lt705r1lns202@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>