fs/fat: remove distractive message in file_fat_read_at()

The message "reading %s\n" may be interesting when
debugging but otherwise it is superfluous.

Only output the message when debugging.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>

fs/fat/fat.c

@@ -1106,7 +1106,7 @@ int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
 	if (ret)
 		goto out_free_both;
 
-	printf("reading %s\n", filename);
+	debug("reading %s\n", filename);
 	ret = get_contents(&fsdata, itr->dent, pos, buffer, maxsize, actread);
 
 out_free_both: