turbostat: Check return value of fscanf

Some systems declare fscanf with the warn_unused_result attribute.  On
such systems, turbostat generates the following warnings:

turbostat.c: In function 'get_core_id':
turbostat.c:1203:8: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result]
turbostat.c: In function 'get_physical_package_id':
turbostat.c:1186:8: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result]
turbostat.c: In function 'cpu_is_first_core_in_package':
turbostat.c:1169:8: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result]
turbostat.c: In function 'cpu_is_first_sibling_in_core':
turbostat.c:1148:8: warning: ignoring return value of 'fscanf', declared with attribute warn_unused_result [-Wunused-result]

Fix these by checking the return value of those four calls to fscanf.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Len Brown <len.brown@intel.com>

tools/power/x86/turbostat/turbostat.c

@@ -1189,7 +1189,10 @@ int cpu_is_first_sibling_in_core(int cpu)
 		perror(path);
 		exit(1);
 	}
-	fscanf(filep, "%d", &first_cpu);
+	if (fscanf(filep, "%d", &first_cpu) != 1) {
+		perror(path);
+		exit(1);
+	}
 	fclose(filep);
 	return (cpu == first_cpu);
 }
@@ -1210,7 +1213,10 @@ int cpu_is_first_core_in_package(int cpu)
 		perror(path);
 		exit(1);
 	}
-	fscanf(filep, "%d", &first_cpu);
+	if (fscanf(filep, "%d", &first_cpu) != 1) {
+		perror(path);
+		exit(1);
+	}
 	fclose(filep);
 	return (cpu == first_cpu);
 }
@@ -1227,7 +1233,10 @@ int get_physical_package_id(int cpu)
 		perror(path);
 		exit(1);
 	}
-	fscanf(filep, "%d", &pkg);
+	if (fscanf(filep, "%d", &pkg) != 1) {
+		perror(path);
+		exit(1);
+	}
 	fclose(filep);
 	return pkg;
 }
@@ -1244,7 +1253,10 @@ int get_core_id(int cpu)
 		perror(path);
 		exit(1);
 	}
-	fscanf(filep, "%d", &core);
+	if (fscanf(filep, "%d", &core) != 1) {
+		perror(path);
+		exit(1);
+	}
 	fclose(filep);
 	return core;
 }