perf inject: Fix use without initialization of local variables

perf inject: Fix use without initialization of local variables

Local variables were missing initialization and command line
processing didn't provide default values.

Fixes: 64eed019f3fce124 ("perf inject: Lazy build-id mmap2 event insertion")
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.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>
Link: https://lore.kernel.org/r/20241211060831.806539-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>