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

This revision adds the following parts:

- machine dependent low level init code
- SoC clocks detection and some utility functions
- Common interface to read/write/modify SoC system control registers, used
by some of the other drivers and utility functions
- simple FDT resets support, based on the fdt_clock implementation already
in the tree. For the moment resets and clocks are managed using these
implementations. I am planning to port those to the new extres framework
in the future, but currently I simply don't have time to do this part too.

Approved by: adrian (mentor)
Sponsored by: Smartcom - Bulgaria AD
Differential Revision: https://reviews.freebsd.org/D5826