pkg/tensorflow-lite: blacklist esp32 architecture

[aabadie]

Contribution description

As proposed in #13133 (comment), this PR blacklists the ESP32 architecture in the tensorflow-lite package.

Testing procedure

• Check that pkg/tensorflow-lite build is forbidden by the build system on esp32 architecture:

BUILD_IN_DOCKER=1 make BOARD=esp32-wroom-32 -C tests/pkg_tensorflow-lite
make: Entering directory '/work/riot/RIOT/tests/pkg_tensorflow-lite'
ESP32_SDK_DIR should be defined as /path/to/esp-idf directory
ESP32_SDK_DIR is set by default to /opt/esp/esp-idf
Some feature requirements are blacklisted: arch_esp32
/work/riot/RIOT/tests/pkg_tensorflow-lite/../../Makefile.include:843: *** You can let the build continue on expected errors by setting CONTINUE_ON_EXPECTED_ERRORS=1 to the command line.  Stop.

Issues/PRs references

This is a workaround for the problem reported in #13133 on ESP32 (details in #13133 (comment))

[gschorcht]

A straightforward change.

[gschorcht]

@aabadie Thanks for providing the change so fast. I had it on my plan for today 😉

[gschorcht]

I removed the CI run test label to make Murdock happy. Running the tests fails for nrf52dk which is not related to this PR. I have checked the Murdock build. tests/pkg_tensorflow-lite isn't compiled for ESP32 boards.

[aabadie]

@fjmolinas, is it ok if I provide a backport ? It seems that the new esp32 toolchain won't be deployed for this release (see RIOT-OS/riotdocker#97 (comment)).