fix(pmu): switch FVP PMUv3 SPIs to PPI

FVP PMUv3 SPIs legacy interrupts are only listed for
cluster #0 and are missing for cluster #1.
This patch changes FVP SPIs to PMUv3 PPI as in
arm_fpga.dtsi, morello.dtsi and n1sdp.dtsi.

Signed-off-by: AlexeiFedorov <Alexei.Fedorov@arm.com>
Change-Id: Ic624cec09ba932666c746ae1a6a4b78b6decde96