drm/sched: Make drm_sched_entity_kill() a public function

drm/sched: Make drm_sched_entity_kill() a public function

Some drivers do not care on teardown whether the last jobs pending in an
entity are actually executed before teardown completed. For such
scenarios, drm_sched_entity_flush() is not the ideal function since it's
intended to wait for jobs to complete.

Make drm_sched_entity_kill() public for that use-case and update the
documentation.

Suggested-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Philipp Stanner <phasta@kernel.org>
Link: https://patch.msgid.link/20260415144956.272506-2-phasta@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>