gpu: nvgpu: APIs to disable/enable all engines' activity

gpu: nvgpu: APIs to disable/enable all engines' activity

Add below APIs to disable/re-enable activity on all
engines
gk20a_fifo_disable_all_engine_activity()
gk20a_fifo_enable_all_engine_activity()

Bug 200133289

Change-Id: Ie01a260d587807a3c1712ee32fe870fbcb08f9cd
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/798747
(cherry picked from commit b16ef2d4763b899dc632dbdbe8c48ea04f709da0)
Reviewed-on: http://git-master/r/805928
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: http://git-master/r/815930
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>