tools/power/x86/intel-speed-select: Use mailbox for CLOS_PM_QOS_CONFIG

Use mailbox to read/write CLOS_PM_QOS_CONFIG instead of read/write to
MMIO offset.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

tools/power/x86/intel-speed-select/isst-config.c

@@ -574,12 +574,6 @@ int isst_send_mbox_command(unsigned int cpu, unsigned char command,
 			if (!ret && !write)
 				*resp = value;
 			break;
-		case CLOS_PM_QOS_CONFIG:
-			ret = isst_send_mmio_command(cpu, PM_QOS_CONFIG_OFFSET,
-						     write, &value);
-			if (!ret && !write)
-				*resp = value;
-			break;
 		case CLOS_STATUS:
 			break;
 		default: