habanalabs/gaudi: sync stream add protection to SOB reset flow

Since we moved the SOB reset flow to workqueue and
not part of the fence release flow, we might reach a
scenario where new context is created while we in the middle
of resetting the SOB.
in such cases the reset may fail due to idle check.
This will mess up the streams sync since the SOB value is invalid.
so we protect this area with a mutex, to delay context creation.

Signed-off-by: farah kassabri <fkassabri@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>