ixgbe: fix DCA dependency in Kconfig

ixgbe can depend on dca IF it is enabled.  So if we are compiled as
IXGBE=y, and DCA is enabled, then we must force INTEL_IOATDMA and therefore
DCA to be =y also.
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/Kconfig

@@ -2411,6 +2411,7 @@ config IXGBE
 	tristate "Intel(R) 10GbE PCI Express adapters support"
 	depends on PCI && INET
 	select INET_LRO
+	select INTEL_IOATDMA
 	---help---
 	  This driver supports Intel(R) 10GbE PCI Express family of
 	  adapters.  For more information on how to identify your adapter, go