forcedeth: Move the NVIDIA nForce driver

Move the nForce driver into drivers/net/ethernet/nvidia/ and make
the necessary Kconfig and Makefile changes.

Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index 711297f..1de8edc 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/drivers/net/ethernet/Kconfig
@@ -86,6 +86,7 @@
 source "drivers/net/ethernet/natsemi/Kconfig"
 source "drivers/net/ethernet/8390/Kconfig"
 source "drivers/net/ethernet/nuvoton/Kconfig"
+source "drivers/net/ethernet/nvidia/Kconfig"
 source "drivers/net/ethernet/octeon/Kconfig"
 source "drivers/net/ethernet/oki-semi/Kconfig"
 source "drivers/net/ethernet/packetengines/Kconfig"