gpio/aspeed-sgpio: don't enable all interrupts by default

Currently, the IRQ setup for the SGPIO driver enables all interrupts in
dual-edge trigger mode. Since the default handler is handle_bad_irq, any
state change on input GPIOs will trigger bad IRQ warnings.

This change applies sensible IRQ defaults: single-edge trigger, and all
IRQs disabled.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Fixes: 7db47faa ("gpio: aspeed: Add SGPIO driver")
Reviewed-by: Joel Stanley <joel@jms.id.au>
Acked-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>