habanalabs: improve MMU cache invalidation code

A new sequence is introduced to invalidate the MMU cache in order to avoid
timeouts.

Signed-off-by: Omer Shpigelman <oshpigelman@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>