Fix typos/wording in various files in doc/.

Signed-off-by: Wolfgang Wallner <wolfgang.wallner@br-automation.com>
Reviewed-by: E Shattow <e@freeshell.de>

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

Update documents 'README.fdt-control' reference to replacement 'control.rst':
  doc/arch/nios2.rst
  dts/Makefile

Also convert some adjacent pathname mentions to rST links where applicable

Fixes: 3e9fddfc4f14 "doc: Move devicetree control doc to rST"
Signed-off-by: E Shattow <e@freeshell.de>

Use only a single -machine parameter.

Describe that the same invocation of qemu-system-<arch> has to be
used for dumping the device-tree as will be used when executing U-Boot.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

Recently we are introducing multiple git subtree projects and
it is the right time to have a universal script to update
various subtrees and replace the dts/update-dts-subtree.sh.

update-subtree.sh is a wrapper of git subtree commands.

Usage: From U-Boot top directory,
run
$ ./tools/update-subtree.sh pull <subtree-name> <release-tag>
for pulling a tag from the upstream.
Or run
$ ./tools/update-subtree.sh pick <subtree-name> <commit-id>
for cherry-pick a commit from the upstream.

Currently <subtree-name> supports dts, mbedtls and lwip.

Signed-off-by: Raymond Mao <raymond.mao@linaro.org>

Document the logic of when we do a full resync of the device trees used
by OF_UPSTREAM as well as that cherry-picking is allowed as needed.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Quentin Schulz <quentin.schulz@cherry.de>

Short reference link names like "dtspec", "dtrepo", "dttweaks" etc.
interrupt the flow of the document text. Lets avoid them and instead
expand in place for better readability.

Suggested-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Paul Barker <paul.barker.ct@bp.renesas.com>

Encourage SoC/board maintainers to migrate to using devicetree-rebasing
subtree and maintain a regular sync with Linux kernel devicetree files
and bindings.

Along with that add documentation regarding how to run DT bindings
schema checks.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>

Since U-Boot switched away from manual CONFIG_* defines to Kconfig
options, align devicetree documentation accordingly.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>