hw/mips: Implement the kvm_type() hook in MachineClass

hw/mips: Implement the kvm_type() hook in MachineClass

MIPS has two types of KVM: TE & VZ, and TE is the default type. Now we
can't create a VZ guest in QEMU because it lacks the kvm_type() hook in
MachineClass. This patch add the the kvm_type() hook to support both of
the two types.

[AM: Added "if defined" guards.]

Reviewed-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
Signed-off-by: Huacai Chen <chenhc@lemote.com>
Co-developed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <1592995531-32600-2-git-send-email-chenhc@lemote.com>