fix(aes): correct the linking of the DMA descriptors

For certain data lengths, the last input descriptor was not getting appended
correctly and hence the EOF flag in the DMA descriptor link list was
set at incorrect location. This was resulting in the peripheral being
stalled expecting more data and eventually the code used to timeout
waiting for the AES completion interrupt.

Required configs for this issue:

CONFIG_MBEDTLS_HARDWARE_AES
CONFIG_SOC_AES_SUPPORT_DMA

This observation is similar to the issue reported in:
https://github.com/espressif/esp-idf/issues/10647

To recreate this issue, start the AES-GCM DMA operation with data length
12280 bytes and this should stall the operation forever.

In this fix, we are tracing the entire descriptor list and then appending the
extra bytes descriptor at correct position (as the last node).

components/mbedtls/port/aes/dma/esp_aes.c

@@ -400,6 +400,10 @@ static int esp_aes_process_dma(esp_aes_context *ctx, const unsigned char *input,
         //Limit max inlink descriptor length to be 16 byte aligned, require for EDMA
         lldesc_setup_link_constrained(block_out_desc, output, block_bytes, LLDESC_MAX_NUM_PER_DESC_16B_ALIGNED, 0);
 
+        /* Setup in/out start descriptors */
+        lldesc_append(&in_desc_head, block_in_desc);
+        lldesc_append(&out_desc_head, block_out_desc);
+
         out_desc_tail = &block_out_desc[lldesc_num - 1];
     }
 
@@ -417,20 +421,13 @@ static int esp_aes_process_dma(esp_aes_context *ctx, const unsigned char *input,
         lldesc_setup_link(&s_stream_in_desc, s_stream_in, AES_BLOCK_BYTES, 0);
         lldesc_setup_link(&s_stream_out_desc, s_stream_out, AES_BLOCK_BYTES, 0);
 
-        if (block_bytes > 0) {
-            /* Link with block descriptors*/
-            block_in_desc[lldesc_num - 1].empty = (uint32_t)&s_stream_in_desc;
-            block_out_desc[lldesc_num - 1].empty = (uint32_t)&s_stream_out_desc;
-        }
+        /* Link with block descriptors */
+        lldesc_append(&in_desc_head, &s_stream_in_desc);
+        lldesc_append(&out_desc_head, &s_stream_out_desc);
 
         out_desc_tail = &s_stream_out_desc;
     }
 
-    // block buffers are sent to DMA first, unless there aren't any
-    in_desc_head =  (block_bytes > 0) ? block_in_desc : &s_stream_in_desc;
-    out_desc_head = (block_bytes > 0) ? block_out_desc : &s_stream_out_desc;
-
-
 #if defined (CONFIG_MBEDTLS_AES_USE_INTERRUPT)
     /* Only use interrupt for long AES operations */
     if (len > AES_DMA_INTR_TRIG_LEN) {