add arm64 support

- add arm64 dependent codes with GICv3 and SVE support
- fix bugs based on architecture separation requests

arch/arm64/kernel/include/arch-string.h

@@ -0,0 +1,13 @@
+/* arch-string.h COPYRIGHT FUJITSU LIMITED 2016-2017 */
+#ifndef __HEADER_ARM64_COMMON_ARCH_STRING_H
+#define __HEADER_ARM64_COMMON_ARCH_STRING_H
+
+#define ARCH_FAST_MEMCPY
+
+extern void *__inline_memcpy(void *to, const void *from, size_t t);
+
+#define ARCH_FAST_MEMSET
+
+extern void *__inline_memset(void *s, unsigned long c, size_t count);
+
+#endif	/* __HEADER_ARM64_COMMON_ARCH_TIMER_H */