tap: tap as an independent module

This patch makes tap a separate module for other types of virtual interfaces, for example,
ipvlan to use.

Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index a993cbe..5763503 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -135,6 +135,7 @@
 	tristate "MAC-VLAN based tap driver"
 	depends on MACVLAN
 	depends on INET
+	select TAP
 	help
 	  This adds a specialized tap character device driver that is based
 	  on the MAC-VLAN network interface, called macvtap. A macvtap device
@@ -287,6 +288,12 @@
 
 	  If you don't know what to use this for, you don't need it.
 
+config TAP
+	tristate
+	---help---
+	  This option is selected by any driver implementing tap user space
+	  interface for a virtual interface to re-use core tap functionality.
+
 config TUN_VNET_CROSS_LE
 	bool "Support for cross-endian vnet headers on little-endian kernels"
 	default n