drm/amd: fix deadlock of job_list_lock V2

run_job involves mutex, which could sleep.

V2: use list_for_each_entry_safe, since the job might complete
while we dropped the lock.

Signed-off-by: Chunming Zhou <David1.Zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>