gpio: pcie-idio-24: Fix IRQ Enable Register value

This fixes the COS Enable Register value for enabling/disabling the
corresponding IRQs bank.

Fixes: 58556204

 ("gpio: Add GPIO support for the ACCES PCIe-IDIO-24 family")
Cc: stable@vger.kernel.org
Signed-off-by: Arnaud de Turckheim <quarium@gmail.com>
Reviewed-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>