fix(cpus): workaround for Cortex-A720 erratum 2926083

Cortex-A720 erratum 2926083 is a Cat B erratum that is present
in revisions r0p0, r0p1 and is fixed in r0p2. The errata is only
present when SPE (Statistical Profiling Extension) is implemented
and enabled.

The workaround is to set bits[58:57] of the CPUACTLR_EL1 to 'b11
when SPE is "implemented and enabled".

SDEN documentation:
https://developer.arm.com/documentation/SDEN2439421/latest

Change-Id: I30182c3893416af65b55fca9a913cb4512430434
Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Signed-off-by: Govindraj Raja <govindraj.raja@arm.com>
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index a7a8c8a..872f6c7 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -940,6 +940,10 @@
 # only to revision r1p0. It is fixed in r1p1.
 CPU_FLAG_LIST += ERRATA_A715_2561034
 
+# Flag to apply erratum 2926083 workaround during reset. This erratum applies
+# to revisions r0p0 and r0p1. It is fixed in r0p2.
+CPU_FLAG_LIST += ERRATA_A720_2926083
+
 # Flag to apply erratum 2940794 workaround during reset. This erratum applies
 # to revisions r0p0 and r0p1. It is fixed in r0p2.
 CPU_FLAG_LIST += ERRATA_A720_2940794