platform_util: Centralize deprecation

Update all files containing MBEDTLS_DEPRECATED to use the definition
from platform_util.h. This avoids duplication across multiple modules
and makes the code easier to read, understand, and maintain.
diff --git a/include/mbedtls/aes.h b/include/mbedtls/aes.h
index 63c0f67..f196ecc 100644
--- a/include/mbedtls/aes.h
+++ b/include/mbedtls/aes.h
@@ -47,6 +47,7 @@
 #include MBEDTLS_CONFIG_FILE
 #endif
 
+#include "mbedtls/platform_util.h"
 #include <stddef.h>
 #include <stdint.h>
 
@@ -619,11 +620,6 @@
                                   unsigned char output[16] );
 
 #if !defined(MBEDTLS_DEPRECATED_REMOVED)
-#if defined(MBEDTLS_DEPRECATED_WARNING)
-#define MBEDTLS_DEPRECATED      __attribute__((deprecated))
-#else
-#define MBEDTLS_DEPRECATED
-#endif
 /**
  * \brief           Deprecated internal AES block encryption function
  *                  without return value.
@@ -651,8 +647,6 @@
 MBEDTLS_DEPRECATED void mbedtls_aes_decrypt( mbedtls_aes_context *ctx,
                                              const unsigned char input[16],
                                              unsigned char output[16] );
-
-#undef MBEDTLS_DEPRECATED
 #endif /* !MBEDTLS_DEPRECATED_REMOVED */