The memory alias support has been removed since a1f4d395 (KVM: Remove
memory alias support). So remove unalias_gfn from the MIPS port.
Reviewed-by: NJames Hogan <james.hogan@imgtec.com>
Signed-off-by: NDeng-Cheng Zhu <dengcheng.zhu@imgtec.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>