Document BAD_STATE errors for multipart operation setup functions

Future commits will implement this and add tests.
diff --git a/include/psa/crypto.h b/include/psa/crypto.h
index 9c59688..ce35e07 100644
--- a/include/psa/crypto.h
+++ b/include/psa/crypto.h
@@ -784,6 +784,9 @@
  *         Success.
  * \retval #PSA_ERROR_NOT_SUPPORTED
  *         \p alg is not supported or is not a hash algorithm.
+ * \retval #PSA_ERROR_BAD_STATE
+ *         The operation state is not valid (already set up and not
+ *         subsequently completed).
  * \retval #PSA_ERROR_INSUFFICIENT_MEMORY
  * \retval #PSA_ERROR_COMMUNICATION_FAILURE
  * \retval #PSA_ERROR_HARDWARE_FAILURE
@@ -1023,6 +1026,9 @@
  * \retval #PSA_ERROR_HARDWARE_FAILURE
  * \retval #PSA_ERROR_TAMPERING_DETECTED
  * \retval #PSA_ERROR_BAD_STATE
+ *         The operation state is not valid (already set up and not
+ *         subsequently completed).
+ * \retval #PSA_ERROR_BAD_STATE
  *         The library has not been previously initialized by psa_crypto_init().
  *         It is implementation-dependent whether a failure to initialize
  *         results in this error code.
@@ -1080,6 +1086,9 @@
  * \retval #PSA_ERROR_HARDWARE_FAILURE
  * \retval #PSA_ERROR_TAMPERING_DETECTED
  * \retval #PSA_ERROR_BAD_STATE
+ *         The operation state is not valid (already set up and not
+ *         subsequently completed).
+ * \retval #PSA_ERROR_BAD_STATE
  *         The library has not been previously initialized by psa_crypto_init().
  *         It is implementation-dependent whether a failure to initialize
  *         results in this error code.
@@ -1325,6 +1334,9 @@
  * \retval #PSA_ERROR_HARDWARE_FAILURE
  * \retval #PSA_ERROR_TAMPERING_DETECTED
  * \retval #PSA_ERROR_BAD_STATE
+ *         The operation state is not valid (already set up and not
+ *         subsequently completed).
+ * \retval #PSA_ERROR_BAD_STATE
  *         The library has not been previously initialized by psa_crypto_init().
  *         It is implementation-dependent whether a failure to initialize
  *         results in this error code.
@@ -1384,6 +1396,9 @@
  * \retval #PSA_ERROR_HARDWARE_FAILURE
  * \retval #PSA_ERROR_TAMPERING_DETECTED
  * \retval #PSA_ERROR_BAD_STATE
+ *         The operation state is not valid (already set up and not
+ *         subsequently completed).
+ * \retval #PSA_ERROR_BAD_STATE
  *         The library has not been previously initialized by psa_crypto_init().
  *         It is implementation-dependent whether a failure to initialize
  *         results in this error code.