powerpc/pseries: Use correct event modifier in rtas_parse_epow_errlog()

rtas_parse_epow_errlog() should pass 'modifier' to
handle_system_shutdown, because event modifier only use
bottom 4 bits.
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191023134838.21280-1-yuehaibing@huawei.com

arch/powerpc/platforms/pseries/ras.c

@@ -255,7 +255,7 @@ static void rtas_parse_epow_errlog(struct rtas_error_log *log)
 		break;
 
 	case EPOW_SYSTEM_SHUTDOWN:
-		handle_system_shutdown(epow_log->event_modifier);
+		handle_system_shutdown(modifier);
 		break;
 
 	case EPOW_SYSTEM_HALT: