Clarify behaviour of psa_validate_key_location

Signed-off-by: Steven Cooreman <steven.cooreman@silabs.com>
diff --git a/library/psa_crypto_slot_management.h b/library/psa_crypto_slot_management.h
index 8841284..46a7325 100644
--- a/library/psa_crypto_slot_management.h
+++ b/library/psa_crypto_slot_management.h
@@ -109,9 +109,10 @@
 psa_status_t psa_validate_key_location( const psa_key_attributes_t *attributes,
                                         psa_se_drv_table_entry_t **p_drv );
 
-/** Validate that a key's persistence is consistent.
+/** Validate that a key's persistence is valid.
  *
- * This function checks whether a key's persistence attribute is consistent.
+ * This function checks whether a key's declared persistence and key ID are
+ * valid and supported by the PSA Core in its actual configuration.
  *
  * \param[in] attributes    The key attributes.
  *