refactor(sdei): use common create_spsr() in SDEI library

The current SPSR updation code as part of the SDEI interrupt handler
code is outdated. This patch replaces the legacy code with a call to
an up-to-date create_spsr()

Change-Id: I1f5fdd41dd14f4b09601310fe881fa3783d7f505
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
3 files changed