bcma: gpio: register 32 GPIOs on BCM5357

Some Broadcom boards have more GPIOs available. For example Linksys
E3200 home router is based on SoC id 0x5357, package 0x0A and uses GPIO
23 to reset internal USB WiFi (gpio23=wombo_reset).

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>