fix(errata): workaround for Cortex X2 erratum 2083908

Cortex X2 erratum 2083908 is a Cat B erratum present in the Cortex
X2 core. It applies to revision r2p0 and is still open.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1775100

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: Id9dca2b042bf48e75fb3013ab37d1c5925824728
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index 0d2c319..b7f9c61 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -142,7 +142,8 @@
 					lib/cpus/aarch64/cortex_a65ae.S		\
 					lib/cpus/aarch64/cortex_a78c.S		\
 					lib/cpus/aarch64/cortex_hayes.S		\
-					lib/cpus/aarch64/cortex_hunter.S
+					lib/cpus/aarch64/cortex_hunter.S	\
+					lib/cpus/aarch64/cortex_x2.S
 	endif
 	# AArch64/AArch32 cores
 	FVP_CPU_LIBS	+=	lib/cpus/aarch64/cortex_a55.S		\