yocto/safety_island: Increase HIPC test timeouts

The HIPC tests have a timeout to terminate the tests if a problem occurs, but
the actual test duration is dependent on the performance of the host machine.
Increase the timeout scale factor of all 4 HIPC test sections to ensure the
tests do not time out on less powerful machines.

Issue-Id: SCM-5864
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Change-Id: I601c56e0807246b1e94bf1ba4681ebf440092ff0