avdevice/dshow: Remove NULL check on pin

The pointer is used before the check

Fixes: CID1591884 Dereference before null check

Sponsored-by: Sovereign Tech Fund
Reviewed-by: Roger Pack <rogerdpack@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 989e11acb6)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavdevice/dshow.c

@@ -431,8 +431,8 @@ dshow_get_device_media_types(AVFormatContext *avctx, enum dshowDeviceType devtyp
             IEnumMediaTypes_Release(types);
         if (p)
             IKsPropertySet_Release(p);
-        if (pin)
-            IPin_Release(pin);
+
+        IPin_Release(pin);
     }
 
     IEnumPins_Release(pins);