plat: tc0: add matterhorn_elp_arm library to tc0

Signed-off-by: Usama Arif <usama.arif@arm.com>
Change-Id: Ie199c60553477c43d1665548ae78cdfd1aa7ffcf

plat/arm/board/tc0/platform.mk

-# Copyright (c) 2020, Arm Limited. All rights reserved.
+# Copyright (c) 2020-2021, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -44,7 +44,8 @@ TC0_BASE	=	plat/arm/board/tc0
 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.S \
+			lib/cpus/aarch64/cortex_matterhorn_elp_arm.S
 
 INTERCONNECT_SOURCES	:=	${TC0_BASE}/tc0_interconnect.c