gpu: nvgpu: restart timer instead of cancel

gpu: nvgpu: restart timer instead of cancel

In gk20a_fifo_handle_sched_error(), we currently cancel
the timeout on all the channels
But this could cause us to miss one of stuck channel

hence, instead of cancelling, restart the timeout of channel
on which it is already active

Bug 200133289

Change-Id: I40e7e0e5394911fc110ab6fde39592b885dfaf7d
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/816133
(cherry picked from commit 7d249416f79e708f4825c9a7265becec0b8c6100)
Reviewed-on: http://git-master/r/820161
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: http://git-master/r/825508
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>