MAINTAINERS: Orphan KVM for MIPS

I haven't been active for 18 months, and don't have the hardware set up
to test KVM for MIPS, so mark it as orphaned and remove myself as
maintainer. Hopefully somebody from MIPS can pick this up.

Signed-off-by: James Hogan <jhogan@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: kvm@vger.kernel.org
Cc: linux-mips@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>