refactor(cpus): register DSU errata with the errata framework's wrappers

The existing DSU errata workarounds hijack the errata framework's inner
workings to register with it. However, that is undesirable as any change
to the framework may end up missing these workarounds. So convert the
checks and workarounds to macros and have them included with the
standard wrappers.

The only problem with this is the is_scu_present_in_dsu weak function.
Fortunately, it is only needed for 2 of the errata and only on 3 cores.
So drop it, assuming the default behaviour and have the callers handle
the exception.

Change-Id: Iefa36325804ea093e938f867b9a6f49a6984b8ae
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 2f9dc65..9b2b139 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -1,5 +1,5 @@
 #
-# Copyright (c) 2013-2024, Arm Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2025, Arm Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -43,7 +43,6 @@
 				bl31/bl31_traps.c				\
 				common/runtime_svc.c				\
 				lib/cpus/errata_common.c			\
-				lib/cpus/aarch64/dsu_helpers.S			\
 				plat/common/aarch64/platform_mp_stack.S		\
 				services/arm_arch_svc/arm_arch_svc_setup.c	\
 				services/std_svc/std_svc_setup.c		\