UI: Set preferHardware only when hw encoder is avail.

streamPage->ui->preferHardware doesn't exist if hw encoder is not
available

Closes obsproject/obs-studio#1665

UI/window-basic-auto-config.cpp

@@ -818,14 +818,15 @@ AutoConfig::AutoConfig(QWidget *parent)
 	if (!hardwareEncodingAvailable) {
 		delete streamPage->ui->preferHardware;
 		streamPage->ui->preferHardware = nullptr;
+	} else {
+		/* Newer generations of NVENC have a high enough quality to
+		 * bitrate ratio that if NVENC is available, it makes sense to
+		 * just always prefer hardware encoding by default */
+		bool preferHardware = nvencAvailable ||
+		                      os_get_physical_cores() <= 4;
+		streamPage->ui->preferHardware->setChecked(preferHardware);
 	}
 
-	/* Newer generations of NVENC have a high enough quality to bitrate
-	 * ratio that if NVENC is available, it makes sense to just always
-	 * prefer hardware encoding by default */
-	bool preferHardware = nvencAvailable || os_get_physical_cores() <= 4;
-	streamPage->ui->preferHardware->setChecked(preferHardware);
-
 	setOptions(0);
 	setButtonText(QWizard::FinishButton,
 			QTStr("Basic.AutoConfig.ApplySettings"));