Minor bug fixes in multicore IRQ spurious test

Program the memory mapped GIC_ITARGETSR register with appropriate
cpu mask and assert the expected value is returned upon reading
the register.

Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>
Change-Id: I356111d763569c229d7f4c9ea3cd4899305a4954
3 files changed