KVM: VMX: Better name x2apic msr bitmaps

Renames x2apic_apicv_inactive msr_bitmaps to x2apic and original
x2apic bitmaps to x2apic_apicv.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>