habanalabs: remove redundant cs validity checks

During TDR handling, we check multiple times if CS is valid.
No need to perform this check as CS must be valid at all time
during the TDR handling.

Signed-off-by: Ofir Bitton <obitton@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>