Workaround for Neoverse N1 erratum 1868343

Neoverse N1 erratum 1868343 is a Cat B erratum, present in older
revisions of the Neoverse N1 processor core.  The workaround is to
set a bit in the CPUACTLR_EL1 system register, which delays instruction
fetch after branch misprediction. This workaround will have a small
impact on performance.

SDEN can be found here:
https://documentation-service.arm.com/static/5f2c130260a93e65927bc92f

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I37da2b3b2da697701b883bff9a1eff2772352844
3 files changed