x86, vdso: Fix the symbol versions on the 32-bit vDSO

The new symbols provide the same API as the 64-bit variants, so they
should have the same symbol version name.  This can't break
userspace, since these symbols are new for 32-bit Linux.

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Cc: Stefani Seibold <stefani@seibold.net>
Link: http://lkml.kernel.org/r/0a869bce03d25619565b1eee7d69a4fd15fd203a.1396124118.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@zytor.com>