ASoC: fsl: add memory to memory function for ASRC

Merge series from Shengjiu Wang <shengjiu.wang@nxp.com>:

This function is base on the accelerator implementation
for compress API:
04177158cf98 ("ALSA: compress_offload: introduce accel operation mode")

Audio signal processing also has the requirement for memory to
memory similar as Video.

This asrc memory to memory (memory ->asrc->memory) case is a non
real time use case.

User fills the input buffer to the asrc module, after conversion, then asrc
sends back the output buffer to user. So it is not a traditional ALSA playback
and capture case.

Because we had implemented the "memory -> asrc ->i2s device-> codec"
use case in ALSA.  Now the "memory->asrc->memory" needs
to reuse the code in asrc driver, so the patch 1 and patch 2 is for refining
the code to make it can be shared by the "memory->asrc->memory"
driver.

Other change is to add memory to memory support for two kinds of i.MX ASRC
modules.