mxs: Make ehci-mxs multiport capable

Rework ehci-mxs so it supports both ports on MX28. It was necessary
to wrap the per-port configuration into struct ehci_mxs_port and pull
out the clock configuration function.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Otavio Salvador <otavio@ossystems.com.br>
Cc: Stefano Babic <sbabic@denx.de>
diff --git a/include/configs/apx4devkit.h b/include/configs/apx4devkit.h
index 73c66af..18c4241 100644
--- a/include/configs/apx4devkit.h
+++ b/include/configs/apx4devkit.h
@@ -182,7 +182,8 @@
 #ifdef CONFIG_CMD_USB
 #define CONFIG_USB_EHCI
 #define CONFIG_USB_EHCI_MXS
-#define CONFIG_EHCI_MXS_PORT		1
+#define CONFIG_EHCI_MXS_PORT1
+#define CONFIG_USB_MAX_CONTROLLER_COUNT	1
 #define CONFIG_EHCI_IS_TDI
 #define CONFIG_USB_STORAGE
 #endif