powernv/opal: Disable OPAL notifier upon poweroff

While we're restarting or powering off the system, we needn't
the OPAL notifier any more. So just to disable that.
Signed-off-by: NGavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/platforms/powernv/setup.c

@@ -93,6 +93,8 @@ static void  __noreturn pnv_restart(char *cmd)
 {
 	long rc = OPAL_BUSY;
 
+	opal_notifier_disable();
+
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_cec_reboot();
 		if (rc == OPAL_BUSY_EVENT)
@@ -108,6 +110,8 @@ static void __noreturn pnv_power_off(void)
 {
 	long rc = OPAL_BUSY;
 
+	opal_notifier_disable();
+
 	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
 		rc = opal_cec_power_down(0);
 		if (rc == OPAL_BUSY_EVENT)