gpio: stmpe: Use seq_putc() in stmpe_dbg_show()

A single character (line break) should be put into a sequence.
Thus use the corresponding function "seq_putc".

This issue was detected by using the Coccinelle software.
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-stmpe.c

@@ -350,7 +350,7 @@ static void stmpe_dbg_show(struct seq_file *s, struct gpio_chip *gc)
 
 	for (i = 0; i < gc->ngpio; i++, gpio++) {
 		stmpe_dbg_show_one(s, gc, i, gpio);
-		seq_printf(s, "\n");
+		seq_putc(s, '\n');
 	}
 }