KVM: Fix WARNING: labels should not be indented in kvm_main.c

WARNING: labels should not be indented
+   out_free_irq_routing:

This patch fixes this WARNING to reduce noise when checking new patches
in kvm_main.c.

Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>