Exynos: Move down common USB configuration

USB is a pretty common feature on exynos 5 board, so it seems sensible
to configure it directly from exynos5-common. As a side-effect this
makes USB available from u-boot on exynos 5420 based boards.

While there enable support for common USB ethernet cards to make it more
likely the default config allows booting for network and enable XHCI on
SMDK5420 which has it defined in the dts but not in its config.

Signed-off-by: Sjoerd Simons <sjoerd.simons@collabora.co.uk>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
diff --git a/include/configs/smdk5420.h b/include/configs/smdk5420.h
index 6b45948..61f582f 100644
--- a/include/configs/smdk5420.h
+++ b/include/configs/smdk5420.h
@@ -34,6 +34,10 @@
 #define CONFIG_IDENT_STRING	" for SMDK5420"
 #define CONFIG_DEFAULT_CONSOLE		"console=ttySAC1,115200n8\0"
 
+/* USB */
+#define CONFIG_USB_XHCI
+#define CONFIG_USB_XHCI_EXYNOS
+
 /* DRAM Memory Banks */
 #define CONFIG_NR_DRAM_BANKS	7
 #define SDRAM_BANK_SIZE		(512UL << 20UL)	/* 512 MB */