powerpc/configs/microwattt: Enable Liteeth

Liteeth is the network device used by Microwatt.
Signed-off-by: NJoel Stanley <joel@jms.id.au>
Signed-off-by: NMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210826122653.3236867-3-joel@jms.id.au

arch/powerpc/configs/microwatt_defconfig

@@ -53,6 +53,7 @@ CONFIG_MTD_SPI_NOR=y
 CONFIG_BLK_DEV_LOOP=y
 CONFIG_BLK_DEV_RAM=y
 CONFIG_NETDEVICES=y
+CONFIG_LITEX_LITEETH=y
 # CONFIG_WLAN is not set
 # CONFIG_INPUT is not set
 # CONFIG_SERIO is not set