KVM: Move common KVM Kconfig items to new file virt/kvm/Kconfig

Reduce Kconfig code duplication.

Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
new file mode 100644
index 0000000..79e83fc
--- /dev/null
+++ b/virt/kvm/Kconfig
@@ -0,0 +1,7 @@
+# KVM common configuration items and defaults
+
+config HAVE_KVM
+       bool
+
+config HAVE_KVM_IRQCHIP
+       bool