bootloader: Fix esp_get_flash_encryption_mode(). RELEASE = (CRYPT_CNT == max) or (CRYPT_CNT.write_protect == true)

If the CRYPT_CNT efuse is max it means the same as a write protection bit for this efuse.

Closes: https://github.com/espressif/esp-idf/issues/5747

components/bootloader_support/src/flash_encrypt.c

@@ -70,14 +70,23 @@ void esp_flash_write_protect_crypt_cnt()
 
 esp_flash_enc_mode_t esp_get_flash_encryption_mode()
 {
-    uint8_t efuse_flash_crypt_cnt_wr_protected = 0;
+    uint8_t flash_crypt_cnt_wr_dis = 0;
     uint8_t dis_dl_enc = 0, dis_dl_dec = 0, dis_dl_cache = 0;
     esp_flash_enc_mode_t mode = ESP_FLASH_ENC_MODE_DEVELOPMENT;
 
     if (esp_flash_encryption_enabled()) {
         /* Check if FLASH CRYPT CNT is write protected */
-        esp_efuse_read_field_blob(ESP_EFUSE_WR_DIS_FLASH_CRYPT_CNT, &efuse_flash_crypt_cnt_wr_protected, 1);
-        if (efuse_flash_crypt_cnt_wr_protected) {
+
+        esp_efuse_read_field_blob(ESP_EFUSE_WR_DIS_FLASH_CRYPT_CNT, &flash_crypt_cnt_wr_dis, 1);
+        if (!flash_crypt_cnt_wr_dis) {
+            uint8_t flash_crypt_cnt = 0;
+            esp_efuse_read_field_blob(ESP_EFUSE_FLASH_CRYPT_CNT, &flash_crypt_cnt, ESP_EFUSE_FLASH_CRYPT_CNT[0]->bit_count);
+            if (flash_crypt_cnt == (1 << (ESP_EFUSE_FLASH_CRYPT_CNT[0]->bit_count)) - 1) {
+                flash_crypt_cnt_wr_dis = 1;
+            }
+        }
+
+        if (flash_crypt_cnt_wr_dis) {
             esp_efuse_read_field_blob(ESP_EFUSE_DISABLE_DL_CACHE, &dis_dl_cache, 1);
             esp_efuse_read_field_blob(ESP_EFUSE_DISABLE_DL_ENCRYPT, &dis_dl_enc, 1);
             esp_efuse_read_field_blob(ESP_EFUSE_DISABLE_DL_DECRYPT, &dis_dl_dec, 1);