feat(sve): enable SVE for the secure world

Enables SVE support for the secure world via ENABLE_SVE_FOR_SWD.
ENABLE_SVE_FOR_SWD defaults to 0 and has to be explicitly set by the
platform. SVE is configured during initial setup and then uses EL3
context save/restore routine to switch between SVE configurations for
different contexts.
Reset value of CPTR_EL3 changed to be most restrictive by default.

Signed-off-by: Max Shvetsov <maksims.svecovs@arm.com>
Change-Id: I889fbbc2e435435d66779b73a2d90d1188bf4116
diff --git a/include/lib/extensions/sve.h b/include/lib/extensions/sve.h
index 83df177..c85e08c 100644
--- a/include/lib/extensions/sve.h
+++ b/include/lib/extensions/sve.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2021, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -7,9 +7,8 @@
 #ifndef SVE_H
 #define SVE_H
 
-#include <stdbool.h>
+#include <context.h>
 
-bool sve_supported(void);
-void sve_enable(bool el2_unused);
+void sve_enable(cpu_context_t *context);
 
 #endif /* SVE_H */