update the interrupt diagrams ...

- Redraw the interrupt diagrams with dia tool
   - Change TSP_HANDLED_S_EL1_FIQ to TSP_HANDLED_S_EL1_INTR in sec-int-handling.png
   - Use the makefile generate the image to avoid unnessary generate
   - Add dia source code

Change-Id: I016022ca964720e8497c27c88a3f371459abc284

Signed-off-by: Qixiang Xu <qixiang.xu@arm.com>