Fix copypasta in lifetime function descriptions
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index b18e220..83e941f 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -596,9 +596,8 @@
 /** \brief Retrieve the lifetime of a key slot.
  *
  * The assignment of lifetimes to slots is implementation-dependent.
- * \param key           Slot whose content is to be exported. This must
- *                      be an occupied key slot.
  *
+ * \param key           Slot to query.
  * \param lifetime      On success, the lifetime value.
  *
  * \retval PSA_SUCCESS
@@ -615,9 +614,8 @@
  * whether the lifetime of an occupied key slot can be changed, is
  * implementation-dependent.
  *
- * \param key           Slot whose content is to be exported. This must
- *                      be an occupied key slot.
- * \param lifetime      The lifetime value to be set for the given key.
+ * \param key           Slot whose lifetime is to be changed.
+ * \param lifetime      The lifetime value to set for the given key slot.
  *
  * \retval PSA_SUCCESS
  *         Success.