MFC r330599:
Fix potential deadlock in command mode change in mlx5core.

Call command completion handler in case of timeout when working in
interrupts mode. Avoid flushing the commands workqueue after acquiring
the semaphores to prevent a potential deadlock.

linux commit 9cba4ebcf374c3772f6eb61f2d065294b2451b49

Sponsored by: Mellanox Technologies