Allow esptool's download stub to be disabled by other options and applications

Currently USB CDC Download requires the `--no-stub` option of `esptool`. This change inverts the Kconfig option to negative, so that it can be `selected` by other options or enabled in applications through `sdkconfig.defaults`.

components/bootloader/Kconfig.projbuild

@@ -763,6 +763,7 @@ menu "Security features"
     config SECURE_ENABLE_SECURE_ROM_DL_MODE
         bool "Permanently switch to ROM UART Secure Download mode"
         depends on SECURE_TARGET_HAS_SECURE_ROM_DL_MODE && !SECURE_DISABLE_ROM_DL_MODE
+        select ESPTOOLPY_NO_STUB
         help
             If set, during startup the app will burn an eFuse bit to permanently switch the UART ROM
             Download Mode into a separate Secure Download mode. This option can only work if

components/esptool_py/CMakeLists.txt

@@ -27,10 +27,10 @@ if(NOT BOOTLOADER_BUILD)
     set(ESPTOOLPY_BEFORE "${CONFIG_ESPTOOLPY_BEFORE}")
     set(ESPTOOLPY_AFTER  "${CONFIG_ESPTOOLPY_AFTER}")
     set(ESPTOOLPY_CHIP "${target}")
-    if(CONFIG_ESPTOOLPY_WITH_STUB)
-        set(ESPTOOLPY_WITH_STUB true)
-    else()
+    if(CONFIG_ESPTOOLPY_NO_STUB)
         set(ESPTOOLPY_WITH_STUB false)
+    else()
+        set(ESPTOOLPY_WITH_STUB true)
     endif()
 
     if(CONFIG_SECURE_BOOT OR CONFIG_SECURE_FLASH_ENC_ENABLED)

components/esptool_py/Kconfig.projbuild

@@ -54,11 +54,12 @@ menu "Serial flasher config"
             decompress it on the fly before flashing it. For most payloads, this should result in a
             speed increase.
 
-    config ESPTOOLPY_WITH_STUB
-        # Only real reason to disable this is when ESP32-S2 Secure Download Mode is set
-        bool
-        default "y"
-        depends on !SECURE_ENABLE_SECURE_ROM_DL_MODE
+    config ESPTOOLPY_NO_STUB
+        bool "Disable download stub"
+        default "n"
+        help
+            The flasher tool sends a precompiled download stub first by default. That stub allows things
+            like compressed downloads and more. Usually you should not need to disable that feature
 
     choice ESPTOOLPY_FLASHMODE
         prompt "Flash SPI mode"

components/esptool_py/project_include.cmake

@@ -153,7 +153,7 @@ else()
     list(APPEND esptool_flash_main_args "--after=${CONFIG_ESPTOOLPY_AFTER}")
 endif()
 
-if(NOT CONFIG_ESPTOOLPY_WITH_STUB)
+if(CONFIG_ESPTOOLPY_NO_STUB)
     list(APPEND esptool_flash_main_args "--no-stub")
 endif()