ASoC: mxs: mxs-saif: Split mxs_saif_dai into two elements

Running "aplay -l" and "arecord -l" results in the following outputs:

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: mxssgtl5000 [mxs_sgtl5000], device 0: Playback sgtl5000-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: mxssgtl5000 [mxs_sgtl5000], device 1: Capture sgtl5000-1 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: mxssgtl5000 [mxs_sgtl5000], device 0: Playback sgtl5000-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: mxssgtl5000 [mxs_sgtl5000], device 1: Capture sgtl5000-1 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

On mx28 there are two serial audio interface ports (SAIF0 and SAIF1) and each
one of them are unidirectional.

Create a mxs_saif_dai array containing a playback element and a record element.

After this change we can correctly report the capabilities as follows:

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: mxssgtl5000 [mxs_sgtl5000], device 0: HiFi Playback sgtl5000-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

$ arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: mxssgtl5000 [mxs_sgtl5000], device 1: HiFi Capture sgtl5000-1 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
ASoC: pcm: Require both CODEC and CPU support when declaring stream caps

When declaring playback and capture capabilities check for both CODEC
side and CPU side support rather than only checking for CODEC side
support.  While it is unusual some CPUs do have unidirectional DAIs.

Signed-off-by: Mark Brown <broonie@kernel.org>