firmware: tee_bnxt: Fix multiple call to tee_client_close_context

Fix calling multiple tee_client_close_context in case of shm allocation
fails.

Fixes: 24688095

 (“firmware: broadcom: add OP-TEE based BNXT f/w manager”)
Signed-off-by: Vikas Gupta <vikas.gupta@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>