SPM: Change data type of irq line to uint32_t

This patch changes the data type of irq line from IRQn_Type to
uint32_t to remove the platform dependency.
Also updated the get_irq_line_for_signal function to align between
the two models.

Change-Id: Ifc381b913d60797b06facd8ccb5d26ba01327372
Signed-off-by: Kevin Peng <kevin.peng@arm.com>
7 files changed