Copy stable/11@r303970 to releng/11.0 as part of the 11.0-RELEASE
cycle.

Prune svn:mergeinfo from the new branch, and rename it to RC1.

Update __FreeBSD_version.

Use the quarterly branch for the default FreeBSD.conf pkg(8) repo and
the dvd1.iso packages population.

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

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Add support for the Microchip mcp7941x.

This is compatible with the ds1307, but comparing the mcp7941x datasheet vs the
ds1307 code, appears there is one bit placement difference, so that is now
accounted for.

Relnotes: yes

Add a driver for the Dallas/Maxim DS1307, another common i2c RTC.

Many thanks to ian who gently provided me the DS1307 breakout board.

Tested on: Raspberry pi
Differential Revision: https://reviews.freebsd.org/D2022
Reviewed by: rpaulo