x86: convert some existing cpuid disable options to new generic bitmap

This convers nofxsr, mem=nopentium and nosep to use the new
generic cpuid disable bitmap instead of using own variables.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>