GitLab

SSBS support is determined by checking ID_AA64PFR1_EL1 and not
ID_AA64PFR0_EL1.

Fixes ARM-Software/tf-issues#679

Change-Id: I8ecba13b850995ec6a6ede3c2a1e02e69a3a95db
Signed-off-by: Dimitris Papastamos <dimitris.papastamos@arm.com>