feat(tc): add save/restore DSU PMU register support

This patch adds support for preserving DSU PMU registers
over a power cycle in TC platform.

These PMU registers need to be manually saved/restored
because they are part of cluster power domain and OS
doesn't know when DSU is powered OFF.

Change-Id: Ife9573f205d99d092039cb95674e7434bb5f9239
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
diff --git a/plat/arm/board/tc/platform.mk b/plat/arm/board/tc/platform.mk
index 93e26d1..37ca4c6 100644
--- a/plat/arm/board/tc/platform.mk
+++ b/plat/arm/board/tc/platform.mk
@@ -68,6 +68,9 @@
 
 CSS_LOAD_SCP_IMAGES	:=	1
 
+# Save DSU PMU registers on cluster off and restore them on cluster on
+PRESERVE_DSU_PMU_REGS		:= 1
+
 # Include GICv3 driver files
 include drivers/arm/gic/v3/gicv3.mk
 
@@ -128,6 +131,7 @@
 				${TC_BASE}/tc_topology.c	\
 				lib/fconf/fconf.c			\
 				lib/fconf/fconf_dyn_cfg_getter.c	\
+				drivers/arm/css/dsu/dsu.c			\
 				drivers/cfi/v2m/v2m_flash.c		\
 				lib/utils/mem_region.c			\
 				plat/arm/common/arm_nor_psci_mem_protect.c	\