This reverts May 2020 commit a2de860f42 ("cmake: fix tools build
with submodules") that added a dependency on rimage for the entire
`tools/` subdirectory, probably because `smex/ldc.h` included
`rimage/fw.h` (removed in previous commit).
Looking at the code review I can see no apparent attempt to understand
anything, not even a quote of a build error message.
This will hopefully unblock
https://github.com/zephyrproject-rtos/zephyr/pull/37250
Signed-off-by: Marc Herbert <marc.herbert@intel.com>
1d8f68140e
