dtc: Update to 1.7.1

dtc: Update to 1.7.1

Update to dtc to 1.7.1. Change tarball to gzip and drop upstreamed patch
010-both-libraries.patch. Disable tests.

Changes sinve v1.7.0 include:
 * dtc
   * Fix check for 10-bit I2C addresses
   * Improve documentation of -@ option
   * Update to libyaml >= 0.2.3
   * Improvements & fixes for device graph checks
   * Add -L / --local-fixups option
   * Add check for length of interrupt-map properties
 * libfdt
   * Add fdt_path_getprop_namelen()
   * Add fdt_get_symbol() and fdt_get_symbol_namelen()
   * Correct documentation of fdt_path_offset()
   * Correct documentation of fdt_appendprop_addrrange()
   * Validate aliases is fdt_get_alias_namelen()
   * Don't overwrite phandles when applying overlays
   * Require Python 3
 * pylibfdt
   * Support boolean properties
   * Fixes for current Python versions
 * General
   * Assorted bugfixes
   * Assorted build improvements
   * Assorted typo fixes in docs
   * Some additional testcases
   * Move to GitHub Actions based CI

Signed-off-by: Andreas Gnau <andreas.gnau@iopsys.eu>
Link: https://github.com/openwrt/openwrt/pull/16411
Signed-off-by: Robert Marko <robimarko@gmail.com>