Add IT8785E

[cyfdecyf]

I bought a mother with IT8785E chip which is not supported for now. The motherboard web page has Watchdog/GPIO sample code. Reading this sample code, I guess most things should be compatible with other IT87 chip. As the sample code has a 8786 sample code folder, I guess this chip resembles 8786 most.

I make some very small modifications to make it87 module load on this chip. The fan speed results are almost the same to fan speeed values in BIOS. I'm not familiar with voltage values so those are not throughly verified.

Note that this chip on motherboard is using index register 0x4e. Not sure whether this is determined by chip or by motherboard.

The motherboard has 2 fans but only fan1 is recongnized at first. I tested all the GPIO registers' values by adding printing code and here's the result:

it87: gpio1 reg value 0x67
it87: gpio2 reg value 0xcc
it87: gpio3 reg value 0xec
it87: gpio4 reg value 0xc3
it87: gpio5 reg value 0x4
it87: gpio9 reg value 0x0

GPIO 4 is the only register that does not skip fan so I used this register. But the value of this register will skip pwm, which I guess is not correct because the motherboard has 4 pin pwm fan connector.