bootloader: create public bootloader_flash.h header

Move non-public functions into bootloader_flash_priv.h header

components/bootloader_support/src/esp32s2/flash_encrypt.c

@@ -14,7 +14,7 @@
 
 #include <strings.h>
 
-#include "bootloader_flash.h"
+#include "bootloader_flash_priv.h"
 #include "bootloader_random.h"
 #include "bootloader_utility.h"
 #include "esp_image_format.h"
@@ -299,8 +299,8 @@ static esp_err_t encrypt_bootloader(void)
         if (err != ESP_OK) {
             ESP_LOGE(TAG, "Failed to encrypt bootloader in place: 0x%x", err);
             return err;
-        } 
-        
+        }
+
         ESP_LOGI(TAG, "bootloader encrypted successfully");
         return err;
     }