feat: add register definitions needed for SMCCC_ARCH_FEATURE_AVAILABILITY

Also slightly optimised some redundant feature functions

Co-developed-by: Charlie Bareham <charlie.bareham@arm.com>
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: I6dcc11060a2f3697a8aa41443e9cfc665b2b7c74
diff --git a/include/common/test_helpers.h b/include/common/test_helpers.h
index fe29ee5..6f97bb3 100644
--- a/include/common/test_helpers.h
+++ b/include/common/test_helpers.h
@@ -212,7 +212,7 @@
 
 #define SKIP_TEST_IF_TRBE_NOT_SUPPORTED()					\
 	do {									\
-		if (!get_armv9_0_trbe_support()) {				\
+		if (!is_feat_trbe_present()) {					\
 			tftf_testcase_printf("ARMv9-TRBE not supported\n");	\
 			return TEST_RESULT_SKIPPED;				\
 		}								\