Eliminate some warnings.

arch/arm/src/lc823450/lc823450_ipl2.c

@@ -681,6 +681,8 @@ int ipl2_main(int argc, char *argv[])
 {
   int ret;
 
+  UNUSED(ret); /* Not used in all configurations */
+
   _info("start: %s\n", CONFIG_CURRENT_REVISION);
   _info("imgsig: %u\n", IMG_SIGNATURE);
 

libnx/nxfonts/nxfonts_cache.c

@@ -353,6 +353,9 @@ static inline void nxf_fillglyph(FAR struct nxfonts_fcache_s *priv,
   int row;
   int col;
 
+  UNUSED(row); /* Not used in all configurations */
+  UNUSED(col);
+
   /* Initialize the glyph memory to the background color. */
 
 #if !defined(CONFIG_NXFONTS_DISABLE_1BPP) || !defined(CONFIG_NXFONTS_DISABLE_2BPP) || \