Update the cpp include flags for compiling device tree dts files
to match the changes made to the kernel build process in
commit d5d332d3 ("devicetree: Move include prefixes from arch
to separate directory").

Cc: <stable@vger.kernel.org> # 4.12
Signed-off-by: NFrank Rowand <frank.rowand@sony.com>
Signed-off-by: NRob Herring <robh@kernel.org>

As the comparison uses process substitution to pass files after
conversion to DTS format, the diff header doesn't show the real
filenames, but the names of the file descriptors used:

    --- /dev/fd/63  2017-06-22 11:21:47.531637188 +0200
    +++ /dev/fd/62  2017-06-22 11:21:47.531637188 +0200

This is especially annoying when comparing a bunch of DT files in a
loop, as the output doesn't show a clue about which files it refers to.

Fix this by explicitly passing the original file names to the diff
command using the --label option, giving e.g.:

    --- arch/arm/boot/dts/r8a7791-koelsch.dtb
    +++ arch/arm/boot/dts/r8a7791-porter.dtb
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NFrank Rowand <frank.rowand@sony.com>
Signed-off-by: NRob Herring <robh@kernel.org>

Determining which kernel config options need to be enabled for a
given devicetree can be a painful process.  Create a new tool to
find the drivers that may match a devicetree node compatible,
find the kernel config options that enable the driver, and
optionally report whether the kernel config option is enabled.
Signed-off-by: NGaurav Minocha <gaurav.minocha.os@gmail.com>
Signed-off-by: NFrank Rowand <frank.rowand@am.sony.com>
Signed-off-by: NRob Herring <robh@kernel.org>

If kernel config options are not properly set, "make scripts" will not
compile dtc.  Update the unable to find dtc error message to check
the kernel config and give better advice on how to create dtc.

Reword another error message to increase clarity.
Signed-off-by: NFrank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: NRob Herring <robh@kernel.org>

Create script to diff device trees.

The device tree can be in any of the forms recognized by the dtc compiler:
  - source
  - binary blob
  - file system tree (from /proc/devicetree)

If the device tree is a source file, then it is pre-processed in the
same way as it would be when built in the linux kernel source tree
before diffing.
Signed-off-by: NFrank Rowand <frank.rowand@sonymobile.com>
Signed-off-by: NRob Herring <robh@kernel.org>