auxdisplay: charlcd: replace octal literal with form-feed escape sequence

There is no need to resort to octal escape sequence for the form feed
character when an established escape sequence exists.
Signed-off-by: Robert Abel <rabel@robertabel.eu>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

drivers/auxdisplay/charlcd.c

@@ -556,7 +556,7 @@ static void charlcd_write_char(struct charlcd *lcd, char c)
 			/* back one char again */
 			lcd->ops->write_cmd(lcd, LCD_CMD_SHIFT);
 			break;
-		case '\014':
+		case '\f':
 			/* quickly clear the display */
 			charlcd_clear_fast(lcd);
 			break;