Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Use DEVMETHOD_END macro defined in sys/bus.h instead of {0, 0} sentinel on device_method_t arrays

Reviewed by: cognet
Approved by: cognet

- Rename ds1672 and ds133x devices to "ds1672_rtc" and "ds133x_rtc"
respectivly. This will allow one to have a kernel with both devices
present and use it for multiple boards with different types of RTC
sitting on a bus.

Discussed with: imp

Clean out some empty mergeinfo records, presumably by people doing local
cp/mv operations. The full repo-relative URL should be specified for the
source in these cases.

Streamline #include sections in ds133x and ds1672 drivers. This unbreaks the
LINT build.

ds133x: Introduce device_identify method; update NOTES.

Obtained from: Semihalf

Rework Dallas Semiconductor RTC support.

- Extend the DS1339 driver to recognize more chips in the family:
DS1337, DS1338, DS1339 are now supported
- Provide run-time chip detection

Reviewed, tested by: stas
Obtained from: Piotr Ziecik kosmo ! semihalf dot com

Rename ds1339 -> ds133x to better fit the upcoming driver extensions.

- Reflect changes in iic infrastructure.

- Add driver for Dallas Semiconductor DS1339 RTC sitting
on I2C bus.

Reviewed by: raj
Approved by: imp
MFC after: 2 week