feat(bt): Frees BLE memory when no longer in use

It will free libble.a & libbt all txt, data and bss segment memory.
          This memory is combined into one large memory and put into the heap
          pool.

docs/en/api-guides/performance/ram-usage.rst

@@ -161,6 +161,7 @@ The following options will reduce IRAM usage of some ESP-IDF features:
     - Setting :ref:`CONFIG_HAL_DEFAULT_ASSERTION_LEVEL` to disable assertion for HAL component saves some IRAM, especially for HAL code who calls ``HAL_ASSERT`` a lot and resides in IRAM.
     - Refer to the sdkconfig menu ``Auto-detect Flash chips``, and you can disable flash drivers which you do not need to save some IRAM.
     - Enable :ref:`CONFIG_HEAP_PLACE_FUNCTION_INTO_FLASH`. Provided that :ref:`CONFIG_SPI_MASTER_ISR_IN_IRAM` is not enabled and the heap functions are not incorrectly used from ISRs, this option is safe to enable in all configurations.
+    :esp32c2: - Enable :ref:`CONFIG_BT_RELEASE_IRAM`. Release BT text section and merge BT data, bss & text into a large free heap region when ``esp_bt_mem_release`` is called. This makes Bluetooth unavailable until the next restart, but saving ~22 KB or more of IRAM.
 
 .. only:: esp32
 

docs/zh_CN/api-guides/performance/ram-usage.rst

@@ -161,6 +161,7 @@ IRAM 优化
     - 设置 :ref:`CONFIG_HAL_DEFAULT_ASSERTION_LEVEL` 为禁用 HAL 组件的断言，可以节省 IRAM 空间，对于经常调用 ``HAL_ASSERT`` 且位于 IRAM 中的 HAL 代码尤为如此。
     - 要禁用不需要的 flash 驱动程序，节省 IRAM 空间，请参阅 sdkconfig 菜单中的 ``Auto-detect Flash chips`` 选项。
     - 启用 :ref:`CONFIG_HEAP_PLACE_FUNCTION_INTO_FLASH`。只要未启用 :ref:`CONFIG_SPI_MASTER_ISR_IN_IRAM` 选项，且没有从 ISR 中错误地调用堆函数，就可以在所有配置中安全启用此选项。
+    :esp32c2: - 启用 :ref:`CONFIG_BT_RELEASE_IRAM`。 蓝牙所使用的 data，bss 和 text 段已经被分配在连续的RAM区间。当调用 ``esp_bt_mem_release`` 时，这些段都会被添加到 Heap 中。 这将节省约 22 KB 的 RAM。但要再次使用蓝牙功能，需要重启程序。
 
 .. only:: esp32