Before fixing up the device locking and device reset code, I want to do
some cleanups of the hub driver and related areas.  This is the first of a
series of patches for that purpose.

This patch changes all the occurrences of "driverfs" in usbcore to "sysfs"
-- I just couldn't stand seeing the out-of-date name any more (and I kept
confusing it with usbfs, don't know why).

Although I did a "bk mv driverfs.c sysfs.c" when creating the patch, the
exported patch file itself doesn't reflect that very well.  It looks like
driverfs.c was deleted and sysfs.c created from scratch.  If you prefer, I
can resubmit this in a slightly different form, with the file name
unchanged so that you can issue the "bk mv" command in your repository
after applying the patch.