Fix formatting issue in psa_key_agreement() documentation

Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/tf-psa-crypto/include/psa/crypto.h b/tf-psa-crypto/include/psa/crypto.h
index a07a86b..aa58033 100644
--- a/tf-psa-crypto/include/psa/crypto.h
+++ b/tf-psa-crypto/include/psa/crypto.h
@@ -4098,11 +4098,11 @@
  *         This is an attempt to create a persistent key, and there is already
  *         a persistent key with the given identifier.
  * \retval #PSA_ERROR_INVALID_ARGUMENT
- *         \p alg is not a key agreement algorithm, or
- *         \p private_key is not compatible with \p alg,
- *         or \p peer_key is not valid for \p alg or not compatible with
- *         \p private_key.
- *         The output key attributes in \p attributes are not valid:
+ *         * \p alg is not a key agreement algorithm.
+ *         * \p private_key is not compatible with \p alg.
+ *         * \p peer_key is not valid for \p alg or not compatible with
+ *           \p private_key.
+ *         * The output key attributes in \p attributes are not valid:
  *              * The key type is not valid for key agreement output.
  *              * The key size is nonzero, and is not the size of the shared secret.
  *              * The key lifetime is invalid.