These drivers blindly assume that i2c_attach_args::ia_cookie is an FDT / OF
phandle. Instead, extract the phandle from self's devhandle, both eliminating
the reference to ia_cookie and providing an assertion that it is, in fact,
an FDT / OF phandle.

find sensor names etc. on older G5 like PowerMac7,2

branches: 1.10.4; 1.10.14; 1.10.24;
Use DEVICE_COMPAT_EOL.

Since we're using designated initialisers for compat data, we should
use a completely empty initializer for the sentinel.

Use designated initializers and a consistent termination style in
compat_data[].

branches: 1.7.10;
explicitly initialize sensor->state

branches: 1.6.2;
In my quest to make device_compatible_entry (and associated goo)
super-general, it turns out I also made it a little to cumbersome
to use (if my tired fingers are any indication). So, this is a
course-correction -- one string per entry (like of_compat_data,
which it will soon replace), and remove the over-verbose macros.

- Rename iic_compat_match() to iic_compatible_match() and change it
to use the new device_compatible_match() routine. A pointer to
the matching device_compatible_entry is returned if a match is
found.
- Adjust iic_use_direct_match() accordingly.
- i2c drivers now provide device_compatible_entry tables when performing
direct-config matching.
- In the dsrtc driver, take advantage of this new capability to greatly
simplify model selection.

(I'm coming for you next, of_compat_data...)

More cleanup to i2c autoconfiguration:

- Get all of the drivers onto the new match quality constants.
- Introduce a new helper function, iic_use_direct_match(), that has
all of the logic for direct-config matching. If it returns true,
the driver returns the match result (which may be 0). If it returns
false, the driver does indirect-config matching.
- iic_compat_match() now returns a weighted match quality; matches to
lower-indexed "compatible" device property are more-specific matches,
and return a better match quality accordingly.

get EEPROM data from uni_n instead of poking around in OF

branches: 1.2.2;
remove some unused code, add comments for credits & explanations

yet another temperature sensor / ADC
this one supports Analog Devices AD7417, found in some G5 macs
depends on OpenFirmware for calibration data