Rename kumalloc to kumm_malloc and kuzalloc to kumm_zalloc for consistency with other naming

audio/audio.c

@@ -530,7 +530,7 @@ static int audio_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
             }
           else
             {
-              /* Perform a simple kumalloc operation assuming 1 session */
+              /* Perform a simple kumm_malloc operation assuming 1 session */
 
               ret = apb_alloc(bufdesc);
             }

audio/pcm_decode.c

@@ -949,7 +949,7 @@ static int pcm_resume(FAR struct audio_lowerhalf_s *dev)
  *   lower-half driver with the opportunity to perform special buffer
  *   allocation if needed, such as allocating from a specific memory
  *   region (DMA-able, etc.).  If not supplied, then the top-half
- *   driver will perform a standard kumalloc using normal user-space
+ *   driver will perform a standard kumm_malloc using normal user-space
  *   memory region.
  *
  ****************************************************************************/