ACPI: suppress compiler warnings in processor_throttling.c

This patch fixes following compiler warnings when build via make W=1:

drivers/acpi/processor_throttling.c: In function ‘acpi_processor_throttling_init’:
drivers/acpi/processor_throttling.c:216:40: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]

Signed-off-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

drivers/acpi/processor_throttling.c

···
  */
 void acpi_processor_throttling_init(void)
 {
-	if (acpi_processor_update_tsd_coord())
+	if (acpi_processor_update_tsd_coord()) {
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 			"Assume no T-state coordination\n"));
+	}
 
 	return;
 }