fix(cpus): workaround for Cortex-A710 2216384

Cortex-A710 erratum 2216384 is a Cat B erratum that applies to revisions
r0p0, r1p0, and r2p0, and is fixed in r2p1. The workaround is to set
CPUACTLR5_EL1[17] to 1 and applying an instruction patching sequence.
Setting this bit, along with these instructions will prevent the
deadlock, and thereby avoids the reset of the processor.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1775101/latest

Change-Id: I2821591c23f854c12111288ad1fd1aef45db6add
Signed-off-by: Jayanth Dodderi Chidanand <jayanthdodderi.chidanand@arm.com>
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 8a86b61..2c92e47 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -480,6 +480,10 @@
    Cortex-A710 CPU. This needs to be enabled for revision r2p0 of the CPU
    and is fixed in r2p1.
 
+-  ``ERRATA_A710_2216384``: This applies errata 2216384 workaround to
+   Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
+   of the CPU and is fixed in r2p1.
+
 -  ``ERRATA_A710_2282622``: This applies errata 2282622 workaround to
    Cortex-A710 CPU. This needs to be enabled for revisions r0p0, r1p0 and r2p0
    of the CPU and is fixed in r2p1.