fix(morello): configure platform specific secure SPIs

Previous implementation used common CSS interrupts, which do not match
the Morello platform interrupt map. Updated to configure Secure
interrupts according to the Morello TRM and InfraSYSDESIGN4.0
specification.

Signed-off-by: Werner Lewis <werner.lewis@arm.com>
Change-Id: I783a472d92601d86f1844f0d035dd0d036b2bfca
1 file changed