Update functional.py (#421)

if on dtype -> elif on dtype

Author: vfdev-5

torchvision/transforms/functional.py

@@ -115,9 +115,9 @@ def to_pil_image(pic, mode=None):
         npimg = npimg[:, :, 0]
         if npimg.dtype == np.uint8:
             expected_mode = 'L'
-        if npimg.dtype == np.int16:
+        elif npimg.dtype == np.int16:
             expected_mode = 'I;16'
-        if npimg.dtype == np.int32:
+        elif npimg.dtype == np.int32:
             expected_mode = 'I'
         elif npimg.dtype == np.float32:
             expected_mode = 'F'