audio: hal and post_proc KW and misc fixes

- KWBUG-811 fixes for NULL check and correct
pointer dereferece in HAL and post_proc

- KWBUG-813, KWBUG-883 fixes for strtok,
strcpy, strncpy strcat, strncat etc.

- Misc fixes for correct pointer dereferencing
  in post_proc

Change-Id: I1a9626a7951aa3d54fb2d92a9167e5f92b5f523f