nuvoton: Move the Nuvoton driver

Move the Nuvoton driver into drivers/net/ethernet/nuvoton/ and
make the necessary Kconfig and Makefile changes.

CC: Wan ZongShun <mcuos.com@gmail.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index ee4ebb4..d31fd9e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1127,7 +1127,7 @@
 F:	drivers/input/keyboard/w90p910_keypad.c
 F:	drivers/input/touchscreen/w90p910_ts.c
 F:	drivers/watchdog/nuc900_wdt.c
-F:	drivers/net/arm/w90p910_ether.c
+F:	drivers/net/ethernet/nuvoton/w90p910_ether.c
 F:	drivers/mtd/nand/nuc900_nand.c
 F:	drivers/rtc/rtc-nuc900.c
 F:	drivers/spi/spi_nuc900.c