Add boot/zephyr/Kconfig reference to module.yml

Adding a reference in module.yml to the boot/zephyr/Kconfig will
define the MCUBOOT symbol before it is used/extended elsewhere.

Building with `west build -p always -b nrf52840dk_nrf52840
mcuboot/samples/zephyr_external_config` fails with:

Parsing /home/zephyr/mcuboot_dev/zephyr/Kconfig
/home/zephyr/mcuboot_dev/zephyr/scripts/kconfig/kconfig.py: /home/zephyr/mcuboot_dev/mcuboot/boot/zephyr/Kconfig:674: recursive 'source' of 'Kconfig.zephyr' detected. Check that environment variables are set correctly.
Include path:
/home/zephyr/mcuboot_dev/zephyr/Kconfig:8
Kconfig.zephyr:39
modules/Kconfig:13
/home/zephyr/mcuboot_dev/build/Kconfig/Kconfig.modules:2
/home/zephyr/mcuboot_dev/mcuboot/boot/zephyr/Kconfig:674
CMake Error at /home/zephyr/mcuboot_dev/zephyr/cmake/modules/kconfig.cmake:326 (message):
  command failed with return code: 1
Call Stack (most recent call first):
  /home/zephyr/mcuboot_dev/zephyr/cmake/modules/zephyr_default.cmake:108 (include)
  /home/zephyr/mcuboot_dev/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  /home/zephyr/mcuboot_dev/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
  CMakeLists.txt:6 (find_package)

Building with `west build -p always -b nrf52840dk_nrf52840
mcuboot/boot/zephyr` now fails with:

Parsing /home/zephyr/mcuboot_dev/mcuboot/boot/zephyr/Kconfig
/home/zephyr/mcuboot_dev/zephyr/scripts/kconfig/kconfig.py: /home/zephyr/mcuboot_dev/build/Kconfig/Kconfig.modules:2: recursive 'source' of '/home/zephyr/mcuboot_dev/mcuboot/boot/zephyr/Kconfig' detected. Check that environment variables are set correctly.
Include path:
/home/zephyr/mcuboot_dev/mcuboot/boot/zephyr/Kconfig:674
Kconfig.zephyr:39
modules/Kconfig:13
/home/zephyr/mcuboot_dev/build/Kconfig/Kconfig.modules:2
CMake Error at /home/zephyr/mcuboot_dev/zephyr/cmake/modules/kconfig.cmake:326 (message):
  command failed with return code: 1
Call Stack (most recent call first):
  /home/zephyr/mcuboot_dev/zephyr/cmake/modules/zephyr_default.cmake:108 (include)
  /home/zephyr/mcuboot_dev/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
  /home/zephyr/mcuboot_dev/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
  CMakeLists.txt:44 (find_package)

Signed-off-by: Gregory SHUE <[email protected]>

Author: legrand-gregshue

zephyr/module.yml

@@ -2,3 +2,4 @@ samples:
   - boot/zephyr
 build:
   cmake: ./boot/bootutil/zephyr
+  kconfig: ./boot/zephyr/Kconfig