IIR EQ should be optimized with HiFi3 intrinsics

[singalsu]

GCC built generic C version is slow though it's fast enough for realtime operation while there is not much other processing in firmware. Compilation with xt-xcc gives better performance but good MCPS performance and low power is achieved only with intrinsics optimized code like volume, FIR, and SRC components.

[singalsu]

@jajanusz OK, got it. It's a fairly small task, I'll start doing next week.

[jajanusz]

@singalsu It would be great. However it's low priority task, so feel free to do it only if you have nothing better to do.

[lgirdwood]

@singalsu lets have this for v1.4 since it's a small task, Btw does FIR require the same ?

[singalsu]

@lgirdwood FIR is optimized already since it was hit worst by generic C implementation. Fortunately I did the intrinsics version for year ago OSTS demo.

[singalsu]

@lgirdwood I didn't find time for this, new ETA is beginning of July, after my vacation ends plus need some work days.

[singalsu]

SOF PR #1624 addresses this requirement.

[singalsu]

This can be closed since PR #1624 is merged.