[coreboot] USB changes

[Leandro Dorileo]

Hi Patrick

I have done the changes we discussed previously. Attached follows the
patches. The 2 first patches are just few changes in the reg
functions(*read/write*) so we can use the same functions in both OHCI
and UHCI.

The last patches are related to the changes I proposed to control
function. I`m copying here the commit log message:

"Changed the usb API where the control function first parameter now
is a pointer of endpoint_t instead of a pointer of usbdevice_t.

The previous implementation assumed the first endpoint(index 0) as
control, which is not true, we can have devices with more than a
single control line."

Since MSC device has always a single control endpoint I kept assuming
that, and the changes to the drivers do exactly that, takes the first
endpoint and passes it to control.

I would like to keep those changes upstream already so it can be
easily maintained. Please review and comment.

PS: I`m cc`ing the coreboot mailing list, this way we can have more reviewers.

Thanks in advance....