perf bpf-filter: Fix opts declaration on older libbpfs

perf bpf-filter: Fix opts declaration on older libbpfs

Building perf with LIBBPF_DYNAMIC (ie not the default static linking of
libbpf with perf) is breaking as the libbpf isn't version 1.7 or newer,
where dont_enable is added to bpf_perf_event_opts.

To avoid this breakage add a compile time version check and don't
declare the variable when not present.

Fixes: 5e2ac8e8571df54d ("perf bpf-filter: Enable events manually")
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: bpf@vger.kernel.org
Cc: Hao Ge <gehao@kylinos.cn>
Cc: Ilya Leoshkevich <iii@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>