Add declaration and dummy-definition of mbedtls_cipher_setup_psa()
diff --git a/include/mbedtls/cipher.h b/include/mbedtls/cipher.h
index 5051c12..e7e222c 100644
--- a/include/mbedtls/cipher.h
+++ b/include/mbedtls/cipher.h
@@ -413,6 +413,26 @@
 int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx,
                           const mbedtls_cipher_info_t *cipher_info );
 
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+/**
+ * \brief               This function initializes a cipher context for
+ *                      PSA-based use with the given cipher primitive.
+ *
+ * \note                See #MBEDTLS_USE_PSA_CRYPTO for information on PSA.
+ *
+ * \param ctx           The context to initialize. May not be \c NULL.
+ * \param cipher_info   The cipher to use.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on
+ *                      parameter-verification failure.
+ * \return              #MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the
+ *                      cipher-specific context fails.
+ */
+int mbedtls_cipher_setup_psa( mbedtls_cipher_context_t *ctx,
+                              const mbedtls_cipher_info_t *cipher_info );
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
 /**
  * \brief        This function returns the block size of the given cipher.
  *
diff --git a/library/cipher.c b/library/cipher.c
index 7a012f9..34a8170 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -58,6 +58,10 @@
 #include "mbedtls/cmac.h"
 #endif
 
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+#include "psa/crypto.h"
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
@@ -204,6 +208,14 @@
     return( 0 );
 }
 
+#if defined(MBEDTLS_USE_PSA_CRYPTO)
+int mbedtls_cipher_setup_psa( mbedtls_cipher_context_t *ctx,
+                              const mbedtls_cipher_info_t *cipher_info )
+{
+    return( MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE );
+}
+#endif /* MBEDTLS_USE_PSA_CRYPTO */
+
 int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx,
                            const unsigned char *key,
                            int key_bitlen,