drivers: gpio_sam: fix gpio_sam_write ACCESS_BY_PORT mode
drivers: gpio_sam: fix gpio_sam_write ACCESS_BY_PORT mode

The 'value' param in ACCESS_BY_PORT mode means the state of a port,
one bit represented one pin in param 'value'.

Signed-off-by: qianfan Zhao <0d01fab1932da5a147025f14dd5829cf5bf10d4d@163.com>

finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,explora26/zephyr,punitvara/zephyr,punitvara/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,punitvara/zephyr,punitvara/zephyr,nashif/zephyr,Vudentz/zephyr,nashif/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,explora26/zephyr,explora26/zephyr,Vudentz/zephyr,finikorg/zephyr,ldts/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,ldts/zephyr,Vudentz/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,GiulianoFranchetto/zephyr,finikorg/zephyr,ldts/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,punitvara/zephyr,explora26/zephyr,galak/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,ldts/zephyr,GiulianoFranchetto/zephyr,nashif/zephyr,explora26/zephyr