perf pmu: Fewer const casts

struct pmu_event has const char*s, only unit needs to be non-const for
the sake of passing as an out argument to strtod().

Reduce the const casts from 4 down to 1.
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: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
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: Rob Herring <robh@kernel.org>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230406235256.2768773-1-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/pmu.c

@@ -352,16 +352,16 @@ static int __perf_pmu__new_alias(struct list_head *list, int dirfd, char *name,
 	struct perf_pmu_alias *alias;
 	int ret;
 	char newval[256];
-	char *long_desc = NULL, *topic = NULL, *unit = NULL, *pmu_name = NULL;
+	const char *long_desc = NULL, *topic = NULL, *unit = NULL, *pmu_name = NULL;
 	bool deprecated = false, perpkg = false;
 
 	if (pe) {
-		long_desc = (char *)pe->long_desc;
-		topic = (char *)pe->topic;
-		unit = (char *)pe->unit;
+		long_desc = pe->long_desc;
+		topic = pe->topic;
+		unit = pe->unit;
 		perpkg = pe->perpkg;
 		deprecated = pe->deprecated;
-		pmu_name = (char *)pe->pmu;
+		pmu_name = pe->pmu;
 	}
 
 	alias = malloc(sizeof(*alias));
@@ -419,7 +419,7 @@ static int __perf_pmu__new_alias(struct list_head *list, int dirfd, char *name,
 				desc ? strdup(desc) : NULL;
 	alias->topic = topic ? strdup(topic) : NULL;
 	if (unit) {
-		if (perf_pmu__convert_scale(unit, &unit, &alias->scale) < 0)
+		if (perf_pmu__convert_scale(unit, (char **)&unit, &alias->scale) < 0)
 			return -1;
 		snprintf(alias->unit, sizeof(alias->unit), "%s", unit);
 	}