usb: orion-ehci: Add support for the Armada 3700

- Add a new compatible string for the Armada 3700 SoCs

- add sbuscfg support for orion usb controller driver. For the SoCs
  without hlock, need to program BAWR/BARD/AHBBRST fields in the sbuscfg
  register to guarantee the AHB master's burst would not overrun or
  underrun the FIFO.

- the sbuscfg register has to be set after the usb controller reset,
  otherwise the value would be overridden to 0. In order to do this, the
  reset callback is registered.

[gregory.clement@free-electrons.com: - reword commit and comments
				     - fix error path in ehci_orion_drv_reset()
				     - fix checkpatch warning]
Signed-off-by: Hua Jing <jinghua@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>