habanalabs: Fix memory leak in error flow of context initialization

Add a missing free of the cs_pending array in the error flow of context
initialization.

Fixes: c16d45f4

 ("habanalabs: Use pending CS amount per ASIC")

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>