fix(cpus): workaround for Cortex-A715 erratum 2728106

Cortex-A715 erratum 2728106 is a Cat B(rare) erratum that is present
in revision r0p0, r1p0 and r1p1. It is fixed in r1p2.

The workaround is to execute an implementation specific sequence in
the CPU.

SDEN documentation:
https://developer.arm.com/documentation/SDEN2148827/latest

Change-Id: Ic825f9942e7eb13893fdbb44a2090b897758cbc4
Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
(cherry picked from commit 10134e3556ca61e670017e681eb637889b1bd4f8)
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 872f6c7..b28d90d 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 2728106 workaround during reset. This erratum applies
+# only to revision r0p0, r1p0 and r1p1. It is fixed in r1p2.
+CPU_FLAG_LIST += ERRATA_A715_2728106
+
 # 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