TorchScript single-output fix (#7261)

models/common.py

@@ -406,9 +406,10 @@ class DetectMultiBackend(nn.Module):
     def forward(self, im, augment=False, visualize=False, val=False):
         # YOLOv5 MultiBackend inference
         b, ch, h, w = im.shape  # batch, channel, height, width
-        if self.pt or self.jit:  # PyTorch
-            y = self.model(im) if self.jit else self.model(im, augment=augment, visualize=visualize)
-            return y if val else y[0]
+        if self.pt:  # PyTorch
+            y = self.model(im, augment=augment, visualize=visualize)[0]
+        elif self.jit:  # TorchScript
+            y = self.model(im)[0]
         elif self.dnn:  # ONNX OpenCV DNN
             im = im.cpu().numpy()  # torch to numpy
             self.net.setInput(im)