feat(sys_reg_trace): enable trace system registers access from lower NS ELs

Introduced a build flag 'ENABLE_SYS_REG_TRACE_FOR_NS' to enable trace
system registers access in NS-EL2, or NS-EL1 (when NS-EL2 is
implemented but unused).

Change-Id: Idc1acede4186e101758cbf7bed5af7b634d7d18d
Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
diff --git a/lib/el3_runtime/aarch32/context_mgmt.c b/lib/el3_runtime/aarch32/context_mgmt.c
index 81d793b..2e5b38f 100644
--- a/lib/el3_runtime/aarch32/context_mgmt.c
+++ b/lib/el3_runtime/aarch32/context_mgmt.c
@@ -16,6 +16,7 @@
 #include <context.h>
 #include <lib/el3_runtime/context_mgmt.h>
 #include <lib/extensions/amu.h>
+#include <lib/extensions/sys_reg_trace.h>
 #include <lib/utils.h>
 
 /*******************************************************************************
@@ -136,6 +137,10 @@
 #if ENABLE_AMU
 	amu_enable(el2_unused);
 #endif
+
+#if ENABLE_SYS_REG_TRACE_FOR_NS
+	sys_reg_trace_enable();
+#endif /* ENABLE_SYS_REG_TRACE_FOR_NS */
 #endif
 }