KVM: PPC: Book3S: Fix compile error that occurs with some gcc versions

Some versions of gcc generate a warning that the variable "emulated"
may be used uninitialized in function kvmppc_handle_load128_by2x64().
It would be used uninitialized if kvmppc_handle_load128_by2x64 was
ever called with vcpu->arch.mmio_vmx_copy_nums == 0, but neither of
the callers ever do that, so there is no actual bug.  When gcc
generates a warning, it causes the build to fail because arch/powerpc
is compiled with -Werror.

This silences the warning by initializing "emulated" to EMULATE_DONE.

Fixes: 09f9849 ("KVM: PPC: Book3S: Add MMIO emulation for VMX instructions")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

arch/powerpc/kvm/powerpc.c

@@ -1345,7 +1345,7 @@ static int kvmppc_emulate_mmio_vsx_loadstore(struct kvm_vcpu *vcpu,
 int kvmppc_handle_load128_by2x64(struct kvm_run *run, struct kvm_vcpu *vcpu,
 		unsigned int rt, int is_default_endian)
 {
-	enum emulation_result emulated;
+	enum emulation_result emulated = EMULATE_DONE;
 
 	while (vcpu->arch.mmio_vmx_copy_nums) {
 		emulated = __kvmppc_handle_load(run, vcpu, rt, 8,