auxdisplay: hd44780: Convert to use charlcd_free()

Convert to use charlcd_free() instead of kfree() for sake of type check.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

drivers/auxdisplay/hd44780.c

@@ -271,7 +271,7 @@ static int hd44780_probe(struct platform_device *pdev)
 	return 0;
 
 fail:
-	kfree(lcd);
+	charlcd_free(lcd);
 	return ret;
 }
 
@@ -281,7 +281,7 @@ static int hd44780_remove(struct platform_device *pdev)
 
 	charlcd_unregister(lcd);
 
-	kfree(lcd);
+	charlcd_free(lcd);
 	return 0;
 }