x86/build/vdso: Remove unused vdso-syms.lds

This file contains symbol values, and was originally linked into
vmlinux, but I have no idea what it was actually used for.

Since the following commit:

  827880ec

 ("x86/um: thin archives build fix")

it is not even linked.  Now it is completely orphan, and no problem has
been reported.  It is a proof that this file was not needed in the
first place.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Richard Weinberger <richard@nod.at>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-um@lists.infradead.org
Link: http://lkml.kernel.org/r/1530582614-5173-2-git-send-email-yamada.masahiro@socionext.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>