ehea: Fix missing Kconfig dependency

Fixed Kconfig: ehea driver requires sparse mem
Signed-off-by: Thomas Klein <tklein@de.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/Kconfig

@@ -2519,7 +2519,7 @@ config CHELSIO_T3
 
 config EHEA
 	tristate "eHEA Ethernet support"
-	depends on IBMEBUS && INET
+	depends on IBMEBUS && INET && SPARSEMEM
 	select INET_LRO
 	---help---
 	  This driver supports the IBM pSeries eHEA ethernet adapter.