MAINTAINERS: Add git tree for KVM/mips

There is no git tree for KVM/mips in MAINTAINERS, it is not
convinent to rebase, add it.
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>

MAINTAINERS

@@ -9739,6 +9739,7 @@ M:	Aleksandar Markovic <aleksandar.qemu.devel@gmail.com>
 L:	linux-mips@vger.kernel.org
 L:	kvm@vger.kernel.org
 S:	Maintained
+T:	git git://git.kernel.org/pub/scm/virt/kvm/kvm.git
 F:	arch/mips/include/asm/kvm*
 F:	arch/mips/include/uapi/asm/kvm*
 F:	arch/mips/kvm/