Support psa-arch-tests newer than v25.02_API1.8_CRYPTO_1.2.1

[gilles-peskine-arm]

v25.02_API1.8_CRYPTO_1.2.1 of psa-arch-tests (the PSA API compliance test suite, which we use from test_psa_compliance.py) is the last release that scripts/mbedtls_framework/psa_compliance.py supports as of today. From v25.08_API1.9_ADAC_1.0.2 onwards, we need to initialize the val_common submodule of psa-arch-tests.

Without initializing the val_common submodule, tests_psa_compliance.py fails when it runs cmake in psa-arch-tests with the following error:

CMake Error at CMakeLists.txt:642 (include):
  include could not find requested file:

    /path/to/psa-arch-tests/api-tests/../val_common/common_val.cmake

CMake Error at CMakeLists.txt:659 (add_dependencies):
  Cannot add target-level dependencies to non-existent target
  "common_val_lib".

  The add_dependencies works for top-level logical targets created by the
  add_executable, add_library, or add_custom_target commands.  If you want to
  add file-level dependencies see the DEPENDS option of the add_custom_target
  and add_custom_command commands.


CMake Error at CMakeLists.txt:675 (set_property):
  set_property could not find TARGET common_val_lib.  Perhaps it has not yet
  been created.