fix(errata): add Cortex-A520 definitions

Include the missing Cortex-A520 header.

Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
Change-Id: I45153a1aa2d6dace38650268a32106f5201f48bd
(cherry picked from commit ae19093f2aa6dd95cc7819accb0d05c0ebe4eeb3)
1 file changed