fix(cpus): workaround for Cortex X3 erratum 2641945

Cortex X3 erratum 2641945 is a Cat B erratum that applies to all
revisions <= r1p0 and is fixed in r1p1.

The workaround is to disable the affected L1 data cache prefetcher
by setting CPUACTLR6_EL1[41] to 1. Doing so will incur a performance
penalty of ~1%. Contact Arm for an alternate workaround that impacts
power.

SDEN documentation:
https://developer.arm.com/documentation/2055130/latest

Change-Id: Ia6d6ac8a66936c63b8aa8d7698b937f42ba8f044
Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index a99c082..31430ae 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -794,6 +794,10 @@
 # to revisions r0p0, r1p0, r1p1 of the Cortex-X3 cpu, it is still open.
 CPU_FLAG_LIST += ERRATA_X3_2615812
 
+# Flag to apply erratum 2641945 workaround on reset. This erratum applies
+# to revisions r0p0 and r1p0 of the Cortex-X3 cpu, it is fixed in r1p1.
+CPU_FLAG_LIST += ERRATA_X3_2641945
+
 # Flag to apply erratum 2742421 workaround on reset. This erratum applies
 # to revisions r0p0, r1p0 and r1p1 of the Cortex-X3 cpu, it is fixed in r1p2.
 CPU_FLAG_LIST += ERRATA_X3_2742421