Broadcom BCM53573 SoCs actually have 32 GPIOs, and not 16.

Fixes: 3f37ec79 ("bcma: support BCM53573 series of wireless SoCs")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>