ECHI HCDs: Separate logic used in synchronous transfers so that it can be used in forthcoming asynchronous transfer

Port hub support to LPC31 from SAMA5; Updated Olimex-LPC-H3131 for hub support and refresh configurations

Copy some control port framework from LPC17 to SAMA5 OHCI; Copy some speed handling from SAMA5 OHCI to LPC17

If asynchronous tranfers are supported, then there must also be a mechanism to cancel the pending transfer

Fix USB hub bugs: Don't allocate port EP0 until needed, otherwise run out of endpoints; using wrong pointer to access child endpoint array in a few places

STM32 RTC counter: Include enable/disable backup domain within critical section.  Per recommendtion of Alexander Oryshchenko.

STM32 F1 RTC Counter:  Now need to enable backup domain write access when setting the time.  From Darcy Gong

Fix an error introduced into stm32_pwr_enablebkp().  That function must preserve the previous state of backup domain access on return.