sw:vec_iree: Fix HAL driver setting (trial 2)

Need to force update and cache IREE_HAL_DRIVERS_TO_BUILD to match
https://github.com/google/iree/blob/a547965/CMakeLists.txt#L53

Change-Id: I314b975e259f1f946775843122301318c08e005a
1 file changed
tree: 6befcf3c71d9f8278746a7d7372bd9b1eb08133b
  1. cmake/
  2. native_log_include/
  3. samples/
  4. CMakeLists.txt
  5. springbok_config.h