MFC r282500, r282693:

MFC r282500, r282693:
 r282500:
  Add initial support for building RPI2 images.

  In release.sh, allow overriding buildenv_setup() before
  the handoff to arm/release.sh.

  Copy arm/RPI-B.conf -> arm/RPI2.conf, set UBOOT_PORT and
  the correct KERNEL, and add the buildenv_setup() override
  to install the sysutils/u-boot-rpi2 port/package.

  Copy tools/arm/crochet-RPI-B.conf -> tools/arm/crochet-RPI2.conf,
  and set the correct entries for the RaspberryPi2 board.

 r282693:
  Merge ^/projects/release-arm-redux into ^/head.

  Of note:

  - This commit adds native FreeBSD/arm release build support without
    requiring out-of-tree utilities.

  - Part of this merge removes the WANDBOARD-{SOLO,DUAL,QUAD} kernel
    configuration files, for which the IMX6 kernel configuration file
    should be used instead.

  - The resulting images have a 'freebsd' user (password 'freebsd'),
    to allow ssh(1) access when console access is not available (VGA
    or serial).  The default 'root' user password is set to 'root'.

  - The /etc/ttys file for arm images now enable both ttyv0 and ttyu0
    by default.

Note:  The RPI2 kernel configuration does not yet exist in stable/10,
however the merge conflicts needed to be properly resolved.
Additionally, SRCBRANCH has been set to base/stable/10 in the updated
arm configuration files as part of this commit.

Sponsored by:	The FreeBSD Foundation

git-svn-id: svn://svn.freebsd.org/base/stable/10@283161 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f