Changing the sequence count in update_vsyscall_tz() is completely
pointless.

The vdso code copies the data unprotected. There is no point to change
this as sys_tz is nowhere protected at all. See sys_gettimeofday().
Reviewed-by: NAndy Lutomirski <luto@amacapital.net>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NJohn Stultz <john.stultz@linaro.org>