MLECO-5653: CMSIS-DSP build update

Addressing couple of issues raised here:

* https://github.com/ARM-software/CMSIS-DSP/issues/242
* #1



CMSIS-DSP was previously using MLEK wrapper to set up the
sources and compilation flags. This was done for legacy
reasons that are no longer relevant. With these changes we
rely completely on the CMSIS-DSP project's CMake config to
avoid unnecessary duplication and maintenance cost.

Compile option passed to Arm(R) Compiler `-ffp-mode=full`
has been dropped as it is no longer required. This has been
replaced with recommended `-ffast-math` option instead.

Minor Jinja2 version bump (Python environment requirement)
is also included.

Change-Id: I826d0b4dd3f248cb4d91fe095717805b8d341467
Signed-off-by: Kshitij Sisodia <kshitij.sisodia@arm.com>