feat(realm): add test case for FEAT_DoubleFault2 support on TF-RMM

When FEAT_DoubleFault2 is supported, TF-RMM must take into
account bit SCTLR2_EL1.EASE in order to decide whether to inject
a SEA into the sync exception vector or into the serror one.

The test on this patch verifies that TF-RMM injects the SEA
to the right vector depending on SCTLR2.EASE bit.

Signed-off-by: Javier Almansa Sobrino <javier.almansasobrino@arm.com>
Change-Id: I6c976fecb04d123e3efb96c5973b1466e241097f
diff --git a/realm/realm.mk b/realm/realm.mk
index 305c007..b0536ca 100644
--- a/realm/realm.mk
+++ b/realm/realm.mk
@@ -43,6 +43,7 @@
 	lib/${ARCH}/misc_helpers.S					\
 	lib/smc/${ARCH}/asm_smc.S					\
 	lib/smc/${ARCH}/smc.c						\
+	lib/exceptions/${ARCH}/serror.c					\
 	lib/exceptions/${ARCH}/sync.c					\
 	lib/locks/${ARCH}/spinlock.S					\
 	lib/delay/delay.c						\