lib: el3_runtime: Conditionally save/restore EL2 NEVE registers

Include EL2 registers related to Nested Virtualization in EL2 context
save/restore routines if architecture supports it and platform wants to
use these features in Secure world.

Change-Id: If006ab83bbc2576488686f5ffdff88b91adced5c
Signed-off-by: Arunachalam Ganapathy <arunachalam.ganapathy@arm.com>
diff --git a/lib/el3_runtime/aarch64/context.S b/lib/el3_runtime/aarch64/context.S
index 785e850..c942c10 100644
--- a/lib/el3_runtime/aarch64/context.S
+++ b/lib/el3_runtime/aarch64/context.S
@@ -200,8 +200,10 @@
 	mrs	x12, vdisr_el2
 	str	x12, [x0, #CTX_VDISR_EL2]
 
+#if CTX_INCLUDE_NEVE_REGS
 	mrs	x13, vncr_el2
 	str	x13, [x0, #CTX_VNCR_EL2]
+#endif
 
 	mrs	x14, vsesr_el2
 	str	x14, [x0, #CTX_VSESR_EL2]
@@ -395,8 +397,10 @@
 	ldr	x13, [x0, #CTX_VDISR_EL2]
 	msr	vdisr_el2, x13
 
+#if CTX_INCLUDE_NEVE_REGS
 	ldr	x14, [x0, #CTX_VNCR_EL2]
 	msr	vncr_el2, x14
+#endif
 
 	ldr	x15, [x0, #CTX_VSESR_EL2]
 	msr	vsesr_el2, x15