Add all missing functionality to allow runing Exynos5 EHCI controller inside loader.

Any user application (including loader) should provide three callbacks for allocating resources & ofw parsing:
extern int (*bus_alloc_resource_any_cb)(struct resource *res, device_t dev,

int type, int *rid, unsigned int flags);

extern int (*ofw_bus_status_ok_cb)(device_t dev);
extern int (*ofw_bus_is_compatible_cb)(device_t dev, char *name);