treewide: bump ESP-ADF to 2.6

Bump ESP-ADF to commit 2939a3e541f46f6dd916d2e3b7462609ec4fae5c of our
fork. This is ESP-ADF 2.6 plus our pending and WIP patches.

A new member was introduced to the i2s_stream_cfg_t struct. Set this to
the same value as used in the I2S_STREAM_CFG_DEFAULT() macro. This is
required to avoid a boot loop due to TWDT triggering.

Dockerfile

@@ -27,7 +27,7 @@ COPY container.gitconfig /root/.gitconfig
 ENV PATH="$PATH:/willow/.local/bin"
 WORKDIR /willow
 
-ENV ADF_VER="5cb9820cc1070e629d3439839f4449a61d3c53d6"
+ENV ADF_VER="2939a3e541f46f6dd916d2e3b7462609ec4fae5c"
 RUN \
     cd /opt/esp/idf && \
     curl https://raw.githubusercontent.com/toverainc/esp-adf/$ADF_VER/idf_patches/idf_v4.4_freertos.patch | patch -p1

main/audio.c

@@ -186,6 +186,7 @@ static void init_esp_audio(audio_board_handle_t hdl)
     }
 
     i2s_stream_cfg_t cfg_is = {
+        .buffer_len = I2S_STREAM_BUF_SIZE,
         .expand_src_bits = I2S_BITS_PER_SAMPLE_16BIT,
         .i2s_config = {
             .bits_per_sample = I2S_BITS_PER_SAMPLE_32BIT,
@@ -544,6 +545,7 @@ static void start_rec(void)
     }
 
     i2s_stream_cfg_t cfg_is = {
+        .buffer_len = I2S_STREAM_BUF_SIZE,
         .expand_src_bits = I2S_BITS_PER_SAMPLE_16BIT,
         .i2s_config = {
             .bits_per_sample = I2S_BITS_PER_SAMPLE_16BIT,