sunxi: axp209: Disable interrupts when intializing the axp209

We do not use the axp209 interrupt, and at least in my mini-x (which does not
have a power button) the pwr-button pin and the irq pin are soldered together,
so if the axp209 keeps it irq asserted too long it will see a 10s pwr-button
press and hard power off the board, disabling the irqs fixes this.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>