USB: musb_host: undo incorrect change in musb_advance_schedule()

Commit c9cd06b3

 (musb_host: refactor
URB giveback) included due to my overlook the change incorrect in the
context of the current kernel -- undo it.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>