mvebu: backport mainline patches from kernel 3.12

This is a backport of the patches accepted to the Linux mainline related to
mvebu SoC (Armada XP and Armada 370) between Linux v3.11, and Linux v3.12.
This work mainly covers:

* Ground work for sharing the pxa nand driver(drivers/mtd/nand/pxa3xx_nand.c)
  between the PXA family,and the Armada family.
* Further updates to the mvebu MBus.
* Work and ground work for enabling MSI on the Armada family.
* some phy / mdio bus initialization related work.
* Device tree binding documentation update.

Signed-off-by: Seif Mazareeb <seif.mazareeb@gmail.com>
CC: Luka Perkov <luka@openwrt.org>

SVN-Revision: 39565