Changed the header files included in core.h and io.h to the u-boot header
files so that these files can be included in other dwc3 source files and
be compiled in uboot. Also added otg.h which has the defines for dr_mode.
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
