pinctrl: sunxi: Add irq_chip name

In order to ease the debugging, add a name to the irq_chips.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>