* USB host register definitions added.
* Extracted common register and bitfield definitions
from 'otg_fs.h' and 'otg_hs.h'
into new file 'otg_common.h'.
Modified usb low-level drivers to adopt to new style of bitfields.
* Fixed typo OTG_GOTGIN -> OTG_GOTGINT (according to the datasheet)
Signed-off-by: Amir Hammad <amir.hammad@hotmail.com>