Cactus: helper commands needed for interrupt testing

Following commands added
  1. CACTUS_SLEEP_CMD: request to run cactus in a busy loop for
     given time. Returns time lapsed in this routine.
  2. CACTUS_INTERRUPT_CMD: request to enable/disable given interrupt
     ID, returns success on completion.

Change-Id: I9c7903f1e483d3ea0dc91db5f07135995da77862
Signed-off-by: Manish Pandey <manish.pandey2@arm.com>
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
3 files changed