trusted-keys: match tpm_get_ops on all return paths

The `tpm_get_ops` call at the beginning of the function is not paired
with a `tpm_put_ops` on this return path.

Cc: stable@vger.kernel.org
Fixes: f221974525 ("security: keys: trusted: use ASN.1 TPM2 key format for the blobs")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Ben Boeckel <mathstuf@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>

security/keys/trusted-keys/trusted_tpm2.c

@@ -336,9 +336,9 @@ out:
 			rc = -EPERM;
 	}
 	if (blob_len < 0)
-		return blob_len;
+		rc = blob_len;
-
+	else
-	payload->blob_len = blob_len;
+		payload->blob_len = blob_len;
 
 	tpm_put_ops(chip);
 	return rc;