perf tools: Remove duplicate struct forward declarations

perf tools: Remove duplicate struct forward declarations

'struct evlist' has been declared at 10th line.

'struct comm' has been declared at 15th line.

Remove the duplicates

Signed-off-by: Wan Jiabing <wanjiabing@vivo.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: kael_w@yeah.net
Link: http://lore.kernel.org/lkml/20210325043947.846093-1-wanjiabing@vivo.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>