USB: OHCI: use the ohci structure directly in debugfs files.

Right now we jump through some hoops to get to the struct ohci_hcd
struct in the ohci debugfs files.  Remove all of the fun casting around
and just use the pointer directly.

This is needed as the dev pointer in the hcd structure is going away,
and it makes the code simpler and smaller

Cc: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>