errata: workaround for Neoverse-V1 erratum 2108267

Neoverse-V1 erratum 2108267 is a Cat B erratum that applies to
revisions r0p0, r1p0, and r1p1 of CPU. It is still open. The
workaround is to write the value 2'b11 to the PF_MODE bits in
the CPUECTLR_EL1 register which will place the data prefetcher
in the most conservative mode instead of disabling it.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1401781/latest

Signed-off-by: nayanpatel-arm <nayankumar.patel@arm.com>
Change-Id: Iedcb84a7ad34af7083116818f49d7296f7d9bf94
4 files changed