[PATCHv3 0/8] ALSA: Add SAI driver and enable SGT15000 codec

[Xiubo Li <Li.Xiubo@freescale.com>]

This patch series is mostly Freescale's SAI SoC Digital Audio Interface
driver implementation. And the implementation is only compatible with
device tree definition.

This patch series is based on linux-next and has been tested on Vybrid
VF610 Tower board using device tree.

Changed in v3:
- Add big-endian mode support.
- Revise some commit comments, coding styles,etc.
- Keep header files ordered by alphabet,etc.
- Add MODULE_ALIAS("platform:fsl-sai") for SAI driver.
- Rename the files to be in a same pattern with the existed ones.
- Remove some not useful functions or code.
- Only enable the clock while the device is in active use.
- Revise one error message according to Bill.

Changed in v2:
- Use default settings for the generic dmaengine PCM driver.
- Separate receive and transmit setting in most functions, but some couldn't for the HW limitation.
- Drop some not reduntant code.
- Use devm_snd_soc_register_component() instead of snd_soc_register_component().
- Use devm_snd_soc_register_card() instead of devm_snd_soc_register_card().
- Adjust the code sentences sequence.
- Make the namespacing consistent.
- Rename CONFIG_SND_SOC_FSL_SGTL5000 to CONFIG_SND_SOC_FSL_SGTL5000_VF610.
- Drop some meaningless lines.
- Rename the binding document file.

Added in v1:
- Add SAI SoC Digital Audio Interface driver.
- Add Freescale SAI ALSA SoC Digital Audio Interface node for VF610.
- Enables SAI ALSA SoC DAI device for Vybrid VF610 TOWER board.
- Add device tree bindings for Freescale SAI.
- Revise the bugs about the sgt15000 codec.
- Add SGT15000 based audio machine driver.
- Enable SGT15000 codec based audio driver node for VF610.
- Add device tree bindings for Freescale VF610 sound.