tools/power turbostat: replace strncmp with single character compare

Using strncmp for a single character comparison is overly complicated,
just use a simpler single character comparison instead. Also stops
static analyzers (such as cppcheck) from complaining about strncmp on
non-null terminated strings.
Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Signed-off-by: Len Brown <len.brown@intel.com>

tools/power/x86/turbostat/turbostat.c

@@ -2976,7 +2976,7 @@ int get_thread_siblings(struct cpu_topology *thiscpu)
 				}
 			}
 		}
-	} while (!strncmp(&character, ",", 1));
+	} while (character == ',');
 	fclose(filep);
 
 	return CPU_COUNT_S(size, thiscpu->put_ids);