x86: 64-bit, remove redundant cpu_has_ definitions

PSE, PGE, XMM, XMM2, and FXSR are defined as required features, and
will be optimized to a constant at compile time. Remove their redundant
definitions.

Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>