Cortex-A17: Implement workaround for errata 852423

Change-Id: I3a101e540f0b134ecf9a51fa3d7d8e3d0369b297
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst
index ae0cfd9..ca3366d 100644
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -84,6 +84,9 @@
 -  ``ERRATA_A17_852421``: This applies errata 852421 workaround to Cortex-A17
    CPU. This needs to be enabled only for revision <= r1p2 of the CPU.
 
+-  ``ERRATA_A17_852423``: This applies errata 852423 workaround to Cortex-A17
+   CPU. This needs to be enabled only for revision <= r1p2 of the CPU.
+
 For Cortex-A53, the following errata build flags are defined :
 
 -  ``ERRATA_A53_819472``: This applies errata 819472 workaround to all