Move backward compatibility aliases to their own header

Move backward compatibility aliases to a separate header. Reserve
crypto_extra.h for implementation-specific extensions that we intend
to keep supporting.

This is better documentation for users. New users should simply ignore
backward compatibility aliases, and old users can look at
crypto_compat.h to see what is deprecated without bothering about new
features appearing in crypto_extra.h.

This facilitates maintenance because scripts such as
generate_psa_constants that want to ignore backward compability
aliases can simply exclude crypto_compat.h from their parsing.
diff --git a/include/psa/crypto_extra.h b/include/psa/crypto_extra.h
index c5313d6..62b4c2e 100644
--- a/include/psa/crypto_extra.h
+++ b/include/psa/crypto_extra.h
@@ -32,6 +32,8 @@
 
 #include "mbedtls/platform_util.h"
 
+#include "crypto_compat.h"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -39,21 +41,6 @@
 /* UID for secure storage seed */
 #define PSA_CRYPTO_ITS_RANDOM_SEED_UID 0xFFFFFF52
 
-/*
- * Deprecated PSA Crypto error code definitions
- */
-#if !defined(MBEDTLS_DEPRECATED_REMOVED)
-#define PSA_ERROR_UNKNOWN_ERROR \
-    MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( PSA_ERROR_GENERIC_ERROR )
-#define PSA_ERROR_OCCUPIED_SLOT \
-    MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( PSA_ERROR_ALREADY_EXISTS )
-#define PSA_ERROR_EMPTY_SLOT \
-    MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( PSA_ERROR_DOES_NOT_EXIST )
-#define PSA_ERROR_INSUFFICIENT_CAPACITY \
-    MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( PSA_ERROR_INSUFFICIENT_DATA )
-#define PSA_ERROR_TAMPERING_DETECTED \
-    MBEDTLS_DEPRECATED_NUMERIC_CONSTANT( PSA_ERROR_CORRUPTION_DETECTED )
-#endif
 
 /** \addtogroup attributes
  * @{