Increase NMS fixed time limit 300ms + 30ms/img (ultralytics#7957)

* Increase NMS fixed time limit to 200ms

* Update general.py

utils/general.py

@@ -795,7 +795,7 @@ def non_max_suppression(prediction,
     # min_wh = 2  # (pixels) minimum box width and height
     max_wh = 7680  # (pixels) maximum box width and height
     max_nms = 30000  # maximum number of boxes into torchvision.ops.nms()
-    time_limit = 0.1 + 0.05 * bs  # seconds to quit after
+    time_limit = 0.3 + 0.03 * bs  # seconds to quit after
     redundant = True  # require redundant detections
     multi_label &= nc > 1  # multiple labels per box (adds 0.5ms/img)
     merge = False  # use merge-NMS