[M] Change in coreboot[main]: superio/ite: Add special fan vectors and further options

[Nico Huber (Code Review)]

Attention is currently required from: Joel Linn, Matt DeVillier.

Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/81426?usp=email )

Change subject: superio/ite: Add special fan vectors and further options
......................................................................

Patch Set 1:

(7 comments)

File src/superio/ite/common/env_ctrl.h:

https://review.coreboot.org/c/coreboot/+/81426/comment/da992687_84b281ea :
PS1, Line 211: #define ITE_EC_FAN_VEC_CTL_SLOPESIGN(x)		(((x) & 0x1) << 7)
As many of the bits are in unexpected registers, it might be worth
to put the full register name into the bit definitions, e.g.
```
ITE_EC_FAN_VEC_CTL_SLOPE_TMPIN0(x)
ITE_EC_FAN_VEC_CTL_DELTA_TMPIN1(x)
ITE_EC_FAN_VEC_CTL_DELTA_FANOUT(x)
ITE_EC_FAN_VEC_CTL_RANGE_SLOPE_SIGN(x)
```

File src/superio/ite/common/env_ctrl.c:

https://review.coreboot.org/c/coreboot/+/81426/comment/0cdfc806_d1fbff97 :
PS1, Line 128: 		}
I guess the whole thing should be handled in mainboard code. Then we wouldn't
need the callback nor special values.

You can actually change devicetree settings in ramstage C code, for instance
your mainboard_enable(). e.g.
```
#include <static_devices.h>
...
static void mainboard_enable(struct device *dev)
{
        ...
        __pnp_002e_04->chip->config.ec.tmpin[2].offset = cpu_get_temp_offset();
}
```

https://review.coreboot.org/c/coreboot/+/81426/comment/394057a2_deb728f2 :
PS1, Line 274: 	s8 slope = conf->slope;
             : 	bool slope_neg = slope < 0;
Both should be `const` to show the intention.

https://review.coreboot.org/c/coreboot/+/81426/comment/968104e5_3517200d :
PS1, Line 369: #endif
If trying the 0 array length (see comment in `env_ctrl_chip.h`), this should
become a C `if (CONFIG(SUPERIO_ITE_ENV_CTRL_FAN_VECTOR)) { ... }` so garbage
collection would know that we don't need enable_fan_vector() in the binary.

File src/superio/ite/common/env_ctrl_chip.h:

https://review.coreboot.org/c/coreboot/+/81426/comment/6f6dcb02_665e3a1b :
PS1, Line 106: #endif
As odd as it may seem, GCC accepts a `[0]` here (hopefully clang too). This
would save us from all of the `#if` in C code. e.g. if we did
```
#if CONFIG(SUPERIO_ITE_ENV_CTRL_FAN_VECTOR)
#define ITE_EC_FAN_VECTOR_CNT 2
#else
#define ITE_EC_FAN_VECTOR_CNT 0
#endif
```

File src/superio/ite/common/ite.h:

https://review.coreboot.org/c/coreboot/+/81426/comment/557575bd_2e7afead :
PS1, Line 21: void ite_pme_out_disable(pnp_devfn_t dev);
The other APIs above have the verb first. So how about
`ite_diable_pme_out()`?

https://review.coreboot.org/c/coreboot/+/81426/comment/a613e6b3_62001f62 :
PS1, Line 26: #define ite_disable_3vsbsw(dev) ite_set_3vsbsw((dev), false)
Inline functions are preferred. e.g.
```
static inline void ite_disable_3vsbsw(pnp_devfn_t dev) { ite_set_3vsbsw(dev, false); }
```