RAS: Add fault injection support

The ARMv8.4 RAS extensions introduce architectural support for software
to inject faults into the system in order to test fault-handling
software. This patch introduces the build option FAULT_HANDLING_SUPPORT
to allow for lower ELs to use registers in the Standard Error Record to
inject fault. The build option RAS_EXTENSIONS must also be enabled along
with fault injection.

This feature is intended for testing purposes only, and is advisable to
keep disabled for production images.

Change-Id: I6f7a4454b15aec098f9505a10eb188c2f928f7ea
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
diff --git a/make_helpers/defaults.mk b/make_helpers/defaults.mk
index 791a9c0..4bbff03 100644
--- a/make_helpers/defaults.mk
+++ b/make_helpers/defaults.mk
@@ -76,6 +76,9 @@
 # Build flag to treat usage of deprecated platform and framework APIs as error.
 ERROR_DEPRECATED		:= 0
 
+# Fault injection support
+FAULT_INJECTION_SUPPORT		:= 0
+
 # Byte alignment that each component in FIP is aligned to
 FIP_ALIGN			:= 0