Add support for write protect pins

[julian-poidevin]

The utility does not seem to support dts wp-gpios entries.

I have the following dts node :

eeprom@50{
    compatible = "microchip,24c512", "atmel,24c512";
    wp-gpios = <&gpio4 24 GPIO_ACTIVE_HIGH>; /* set wp-gpios to EEPROM-WP */
    reg = <0x50>;
};

When I use date | eeprog -f -16 -w 0x00 /dev/i2c/by-id/pm 0x50 and then eeprog -f /dev/i2c/by-id/pm 0x50 -16 -r 0x00:0x100 | hexdump -C to read the data back. The data is not properly written into the eeprom.

I should manually set my WP pin to a correct value in order for the data to be properly written.