drm/sched: Fix inverted comment for hang_limit

The hang_limit is the threshold after which the kernel no longer
attempts to schedule a job. Its documentation stated the opposite due to
a typo. Correct the wording to indicate the actual purpose of the field.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210528235152.38447-1-alyssa.rosenzweig@collabora.com