spi_flash: refactor the spi_flash clock configuration, and add support for esp32c2

docs/en/migration-guides/peripherals.rst

@@ -17,6 +17,16 @@ Therefore, the common APIs are extracted to ``esp_rom_spiflash.h``. Although it'
 
 To make the API clearer, we renamed the function ``esp_rom_spiflash_lock`` to ``esp_rom_spiflash_set_bp``. We renamed ``esp_rom_spiflash_unlock`` to ``esp_rom_spiflash_clear_bp``.
 
+ENUM type ``esp_flash_speed_t`` has been deprecated. From now on, you can directly parse the real clock frequency value to the flash initialization structure. For example, if you want the flash frequency is 80M, you can write the code like:
+
+.. code:: c
+
+    esp_flash_spi_device_config_t dev_cfg = {
+        // Other members
+        .freq_mhz = 80,
+        // Other members
+    };
+
 ADC
 ---
 

docs/en/migration-guides/system.rst

@@ -77,3 +77,12 @@ ESP Timer
 ---------
 
 Removed the FRC2 based legacy implementation of esp_timer available on ESP32. The simpler and more efficient implementation based on the LAC timer is now the only option.
+
+ESP image
+---------
+
+Rename the image SPI speed enum definition.
+- Enum ``ESP_IMAGE_SPI_SPEED_80M`` has been renamed to ``ESP_IMAGE_SPI_SPEED_DIV_1``.
+- Enum ``ESP_IMAGE_SPI_SPEED_40M`` has been renamed to ``ESP_IMAGE_SPI_SPEED_DIV_2``.
+- Enum ``ESP_IMAGE_SPI_SPEED_26M`` has been renamed to ``ESP_IMAGE_SPI_SPEED_DIV_3``.
+- Enum ``ESP_IMAGE_SPI_SPEED_20M`` has been renamed to ``ESP_IMAGE_SPI_SPEED_DIV_4``.