KVM: Portability: Move kvm_segment & kvm_dtable structure to <asm/kvm.h>

This patch moves structures:
	kvm_segment
	kvm_dtable
from include/linux/kvm.h to include/asm-x86/kvm.h

Signed-off-by: Jerone Young <jyoung5@us.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>