Changes

[releng] Use build parameter PLATFORM to choose the correct TP

Before, the neon TP was used by default.
Now, we use the PLATFORM paremeter to use the expected TP.

Change-Id: I02d909871a6167fe78ddd8c31da8f8b4f6dd273e
Signed-off-by: Damien Filliat <damien.filliat@thalesgroup.com>