KVM: x86: Remove KF() macro placeholder

Although well-intentioned, keeping the KF() definition as a hint for
handling scattered CPUID features may be counter-productive.  Simply
redefining the bit position only works for directly manipulating the
guest's CPUID leafs, e.g. it doesn't make guest_cpuid_has() magically
work.  Taking an alternative approach, e.g. ensuring the bit position
is identical between the Linux-defined and hardware-defined features,
may be a simpler and/or more effective method of exposing scattered
features to the guest.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>