Correct insufficient memory return documentation.

Signed-off-by: Paul Elliott <paul.elliott@arm.com>
diff --git a/library/psa_crypto_core.h b/library/psa_crypto_core.h
index a007289..5648321 100644
--- a/library/psa_crypto_core.h
+++ b/library/psa_crypto_core.h
@@ -711,8 +711,7 @@
  * \retval #PSA_ERROR_NOT_SUPPORTED Either no internal interruptible operations
  *         are currently supported, or the key type is currently unsupported.
  * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
- *         There was insufficient memory either to load the key representation,
- *         or to store the hash.
+ *         There was insufficient memory to load the key representation.
  */
 psa_status_t mbedtls_psa_sign_hash_start(
     mbedtls_psa_sign_hash_interruptible_operation_t *operation,
@@ -817,7 +816,7 @@
  *         or the key type is currently unsupported.
  * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
  *        There was insufficient memory either to load the key representation,
- *        or to store the hash.
+ *        or to prepare the operation.
  */
 psa_status_t mbedtls_psa_verify_hash_start(
     mbedtls_psa_verify_hash_interruptible_operation_t *operation,