perf evsel: Remove duplicate check for `field` in evsel__intval()

The `file` parameter in evsel__intval() is checked repeatedly, fix it.

No functional change.
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.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: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sandipan Das <sandipan.das@amd.com>
Link: https://lore.kernel.org/r/20230815221009.3641751-1-yangjihong1@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evsel.c

@@ -2827,9 +2827,6 @@ u64 evsel__intval(struct evsel *evsel, struct perf_sample *sample, const char *n
 {
 	struct tep_format_field *field = evsel__field(evsel, name);
 
-	if (!field)
-		return 0;
-
 	return field ? format_field__intval(field, sample, evsel->needs_swap) : 0;
 }
 #endif