Update language to comply with Android's inclusive language guidance

See https://source.android.com/setup/contribute/respectful-code for reference

Bug: 161896447
Change-Id: Iac0b106ef38026b9dc76e906d6df1bdbf627344c
diff --git a/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c b/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c
index ac2ff9a..47b4740 100644
--- a/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c
+++ b/hifi/xaf/hifi-dpf/audio/xa-class-mixer.c
@@ -505,7 +505,7 @@
     {
         XATrack    *track = &mixer->track[idx];
 
-        /* ...input buffer allocation; check track number is sane */
+        /* ...input buffer allocation; check track number is valid */
         XF_CHK_ERR(idx < XA_MIXER_MAX_TRACK_NUMBER, XA_API_FATAL_INVALID_CMD_TYPE);
 
         /* ...create input port for a track */