Merge tag 'at91-dt3' of git://git.kernel.org/pub/scm/linux/kernel/git/nferre/linux-at91 into next/dt

Merge "Third batch of DT changes for 4.2" from Nicolas Ferre:

- USB host clock refine following changes in drivers
- one little fix for usart pinctrl

* tag 'at91-dt3' of git://git.kernel.org/pub/scm/linux/kernel/git/nferre/linux-at91:
  ARM: at91/dt: remove useless usb clock
  ARM: at91/dt: remove useless uhpck clock references from ehci defintions
  USB: atmel: update DT bindings documentation
  ARM: at91/dt: at91sam9x5: fix usart1 sck pin definition