Add stub arm64 linuxulator VDSO ldscript

This needs to be revisited with the VDSO implementation, but is
sufficient to allow the linux64 module to build on arm64 for testing
and development.

Sponsored by:	Turing Robotic Industries

sys/arm64/linux/linux_vdso.lds.s

@@ -0,0 +1,22 @@
+/*
+ * Stub arm64 vdso linker script.
+ * LINUXTODO: update along with VDSO implementation
+ *
+ * $FreeBSD$
+ */
+
+SECTIONS
+{
+	. = . + SIZEOF_HEADERS;
+	.text		: { *(.text*) }
+	.rodata		: { *(.rodata*) }
+	.hash		: { *(.hash) }
+	.gnu.hash	: { *(.gnu.hash) }
+	.dynsym		: { *(.dynsym) }
+	.dynstr		: { *(.dynstr) }
+	.gnu.version	: { *(.gnu.version) }
+	.gnu.version_d	: { *(.gnu.version_d) }
+	.gnu.version_r	: { *(.gnu.version_r) }
+	.data		: { *(.data*) }
+	.dynamic	: { *(.dynamic) }
+}