Build: Use CMAKE_SOURCE_DIR to set default TFM_ROOT_DIR

The default value of TFM_ROOT_DIR is hard-coded to
trusted-firmware-m. But not everyone is using exactly the
same name.
This patch set the default value to CMAKE_SOURCE_DIR, which is
set by CMake command: cmake [options] <path-to-source>, so that
the dependency on the repo name is removed.

Change-Id: I6d1a8028e34cc07e20be8e7671812b2fde6feede
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
2 files changed
tree: 19874b8017b0b595ab3000e06b0312a0a2888f6c
  1. app/
  2. CMSIS/
  3. test/
  4. .gitattributes
  5. .gitignore
  6. dco.txt
  7. license.rst
  8. readme.rst