dtc: update to version 1.7.1 and move to before qemu build

dtc: update to version 1.7.1 and move to before qemu build

- Update from version 1.6.1 to 1.7.1
- Move to before qemu build as it now requires a system libfdt for build as the bundled
   version has been removed.
- Change HOME= to HOME=/usr so that the include files are placed in /usr/include which
   is where qemu is looking for them when it checks that libfdt is available.
- Update disable_Werror patch to take account of differences in the source tarball
- Update of architectures from only aarch64 to all.
- Move rootfile from common/aarch64 to common/
- The previous fdt python files were commented out, hence not used at runtime and are
   not needed at buildtime. From 9.0.1 onwards they require swig and python to be built
   but as they are not needed there was no point to move swig to before dtc
- Changelog
    1.7.1
	 * dtc
	   * Fix -Oasm output on PA-RISC by avoiding ';' separators
	   * Put symbolic label references in -Odts output when possible
	   * Add label relative path references
	   * Don't incorrectly attempt to create fixups for reference to path
	     in overlays
	   * Warning rather than hard error if integer expression results are
	     truncated due to cell size
	 * libfdt
	   * Add fdt_get_property_by_offset_w() function
	 * pylibfdt
	   * Fixed to work with Python 3.10
	   * A number of extra methods
	   * Fix out of tree build
	 * fdtget
	   * Add raw bytes output mode
	 * General
	   * Fixes for mixed-signedness comparison warnings
	   * Assorted other warning fixes
	   * Assorted updates to checks
	   * Assorted bugfixes
	   * Fix scripts to work with dash as well as bash
	   * Allow static builds
	   * Formalize Signed-off-by usage

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>
Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>