Implement DT support for iMX platforms

Meta:
Headline: Add DT support for i.MX6Q
Acceptance: The i.MX6Q initial DT patches hit mainline or arm-soc tree.

Work items were moved to:
https://blueprints.launchpad.net/linux-linaro/+spec/imx-dt-enablement-2011.10
https://blueprints.launchpad.net/linux-linaro/+spec/imx-dt-enablement-2011.11
Please update their status there, not here.

[1] http://thread.gmane.org/gmane.linux.usb.general/55195/focus=55231

Work items for 11.07:
[shawnguo] Add DT support to Serial driver: DONE
[shawnguo] Add DT support to FEC driver: DONE
[shawnguo] Add DT support to SDMA driver: DONE
[shawnguo] Add DT support to MMC driver: DONE
[shawnguo] Add DT support to I2C driver: DONE
[shawnguo] Add DT support to SPI driver: DONE
[shawnguo] Add DT support to GPIO driver: DONE

Work items for 11.09:
[shawnguo] Migrate imx low-level debug support to Will Deacon's Kconfig choice solution: DONE
[shawnguo] Add of_alias_*() support into DT core: DONE
[shawnguo] Add FEC support for imx6q: DONE
[shawnguo] Add chained_irq_enter/exit() into gpio driver to make it work with imx6q: DONE
[shawnguo] Add initial uSDHC support for imx6q: DONE
[shawnguo] Make scu_enable() cope with resume procedure: DONE
[shawnguo] Support imx6q suspend with rmk's suspend infrastructure: DONE
[shawnguo] Add imx local gic_handle_irq() to catch up with imx global move to MULTI_IRQ_HANDLER support: DONE
[shawnguo] Support single zImage build for imx3 and imx6: DONE
[shawnguo] Add initial DT support for i.MX6Q: INPROGRESS
[shawnguo] Write and test DT board description for imx51 eval board: INPROGRESS
[shawnguo] Write and test DT board description for imx53 boards: INPROGRESS
[shawnguo] Add DT binding for IOMUXC for PAD configuration: INPROGRESS
[shawnguo] Add DT support to MC13892 core driver: TODO
[shawnguo] Add DT support to MC13892 regulator driver: TODO
[shawnguo] Migrate imx IOMUXC pinmux support to pinctrl subsystem: TODO
[shawnguo] Consolidate fsl-ssi and imx-ssi drivers: TODO
[shawnguo] Add DT support to SSI driver: TODO
[shawnguo] Add DT support to audio driver: TODO
[shawnguo] Add DT support to USB driver: TODO
[shawnguo] Write and test DT board description for imx51 efika boards: TODO

Work items for 11.12:
[shawnguo] Migrate imx6 clock to common clk v3: DONE
[shawnguo] Add DT support for imx6 clock based on common clk v3 migration and Grant's dt clk binding: DONE

Work items for 12.02:
[shawnguo] Add irqdomain support for IMX: DONE
[shawnguo] Move audmux from arch/arm into ASoC folder: DONE
[shawnguo] Add DT support for audmux driver: DONE
[shawnguo] Merge sound/soc/imx into sound/soc/fsl: DONE
[shawnguo] Make fsl_ssi driver (PowerPC) work for ARM/IMX: DONE

Work items for 12.03:
[shawnguo] Add ASoC machine driver imx-sgtl5000 working with fsl_ssi: DONE
[shawnguo] Add capture support for imx-sgtl5000 audio support: DONE

Work items for 12.04:
[shawnguo] Convert imx6 clock to common clock: TODO
[shawnguo] update https://blueprints.launchpad.net/linaro-power-kernel/+spec/common-clock-port-to-imx when the conversion is done: TODO
[shawnguo] Support imx6 clock DT based on Grant's new dt clk binding: TODO

Work items:
[shawnguo] Reconstruct imx USB driver per discussion [1]: TODO
[shawnguo] Add DT binding for imx USB driver: TODO