fix: rename Matterhorn, Matterhorn ELP, and Klein CPUs

This patch renames the Matterhorn, Matterhorn ELP, and Klein CPUs to
Cortex A710, Cortex X2, and Cortex A510 respectively.

Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I056d3114210db71c2840a24562b51caf2546e195
diff --git a/plat/arm/board/tc0/platform.mk b/plat/arm/board/tc0/platform.mk
index 20ea6e3..814ccd3 100644
--- a/plat/arm/board/tc0/platform.mk
+++ b/plat/arm/board/tc0/platform.mk
@@ -43,9 +43,9 @@
 
 PLAT_INCLUDES		+=	-I${TC0_BASE}/include/
 
-TC0_CPU_SOURCES	:=	lib/cpus/aarch64/cortex_klein.S         \
-			lib/cpus/aarch64/cortex_matterhorn.S \
-			lib/cpus/aarch64/cortex_matterhorn_elp_arm.S
+TC0_CPU_SOURCES	:=	lib/cpus/aarch64/cortex_a510.S         \
+			lib/cpus/aarch64/cortex_a710.S \
+			lib/cpus/aarch64/cortex_x2.S
 
 INTERCONNECT_SOURCES	:=	${TC0_BASE}/tc0_interconnect.c