drivers/gpio: pcal9535a: fix i2c write
drivers/gpio: pcal9535a: fix i2c write

writing to both port registers of pcal9535a
was broken

fixes #17625

Signed-off-by: Chris Schramm <898002ea9fb7639207abf50e6d85dd7c92c35839@makaio.com>

Vudentz/zephyr,finikorg/zephyr,galak/zephyr,Vudentz/zephyr,finikorg/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr