sysctl: x86 Use the compat_sys_sysctl

Now that we have a generic 32bit compatibility implementation
there is no need for x86 to implement it's own.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>