linux-headers: Add unistd_64.h

since 6.11, unistd.h includes header file unistd_64.h directly on
some platforms, here add unistd_64.h on these platforms. Affected
platforms are ARM64, LoongArch64 and Riscv. Otherwise there will
be compiling error such as:

linux-headers/asm/unistd.h:3:10: fatal error: asm/unistd_64.h: No such file or directory
 #include <asm/unistd_64.h>

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Acked-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20241028023809.1554405-2-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>

scripts/update-linux-headers.sh

@@ -163,6 +163,7 @@ EOF
     fi
     if [ $arch = arm64 ]; then
         cp "$hdrdir/include/asm/sve_context.h" "$output/linux-headers/asm-arm64/"
+        cp "$hdrdir/include/asm/unistd_64.h" "$output/linux-headers/asm-arm64/"
     fi
     if [ $arch = x86 ]; then
         cp "$hdrdir/include/asm/unistd_32.h" "$output/linux-headers/asm-x86/"
@@ -185,6 +186,11 @@ EOF
     fi
     if [ $arch = riscv ]; then
         cp "$hdrdir/include/asm/ptrace.h" "$output/linux-headers/asm-riscv/"
+        cp "$hdrdir/include/asm/unistd_32.h" "$output/linux-headers/asm-riscv/"
+        cp "$hdrdir/include/asm/unistd_64.h" "$output/linux-headers/asm-riscv/"
+    fi
+    if [ $arch = loongarch ]; then
+        cp "$hdrdir/include/asm/unistd_64.h" "$output/linux-headers/asm-loongarch/"
     fi
 done
 arch=