feat(timer): support PPI timer interrupts

Add support for timers that use a PPI as timer interrupt. A new
function, tftf_initialise_timer_secondary_core(), is added to initialize
the PPI on the secondary CPUs from tftf_warm_boot_main().

Change-Id: Ia343ce10b0b51e72b9e520b1fab0ea7ba0a43f2c
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
3 files changed