Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Initial storage functionality for U-Boot support library.

- Only non-sliced bsdlabel style partitioning is currently supported (but provisions
are made towards GPT support, which should follow soon)
- Enable storage support in loader on ARM

Obtained from: Semihalf

Initial support of loader(8) for ARM machines running U-Boot.

This uses the common U-Boot support lib (sys/boot/uboot, already used on
FreeBSD/powerpc), and assumes the underlying firmware has the modern API for
stand-alone apps enabled in the config (CONFIG_API).

Only netbooting is supported at the moment.

Obtained from: Marvell, Semihalf