perf config: Introduce perf_config_u8()

Introduce perf_config_u8() utility function to convert char * input into
u8 destination. We will utilize it in followup patch.

Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Taeung Song <treeze.taeung@gmail.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Yisheng Xie <xieyisheng1@huawei.com>
Link: http://lore.kernel.org/lkml/20200213064306.160480-5-ravi.bangoria@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index 0bc9c4d..ef38eba 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -374,6 +374,18 @@ int perf_config_int(int *dest, const char *name, const char *value)
 	return 0;
 }
 
+int perf_config_u8(u8 *dest, const char *name, const char *value)
+{
+	long ret = 0;
+
+	if (!perf_parse_long(value, &ret)) {
+		bad_config(name);
+		return -1;
+	}
+	*dest = ret;
+	return 0;
+}
+
 static int perf_config_bool_or_int(const char *name, const char *value, int *is_bool)
 {
 	int ret;