habanalabs/gaudi: set the correct rc in case of err

fix the following smatch warnings:
gaudi_internal_cb_pool_init() warn: missing error code 'rc'

Signed-off-by: Koby Elbaz <kelbaz@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>