[V2 0/3]Add i.MX51 3-stack board support

[Jason Wang]

Comparing with V1, several changes are made in V2:

1) drop iomux-mx51-3ds.h and move its contents to iomux-mx51.h
2) move keypad device definition to devices.c
3) fix all remaining comments from Sascha, Amit and Fabio.


[V2 1/3] mxc: Add support for the imx51 3-stack board
[V2 2/3] mxc/iomux: add GPIO bank offset for iomux v3 platforms
[V2 3/3] mx51/keypad: add keypad support for i.MX51 platforms