ci: show build failures directly in job log output

ci: show build failures directly in job log output

Instead of waiting for complete workflow finish, then downloading the
artifacts, unpacking them and inspecting them, lets try to make the
build failure immediately visible in the log output:

  ====== Make errors from logs/target/linux/compile.txt ======
  * Legacy (non-UHI/non-FIT) Boards
  *
  Support MIPS SEAD-3 boards (LEGACY_BOARD_SEAD3) [N/y/?] (NEW)
  Error in reading or end of file.

  make[6]: *** [scripts/kconfig/Makefile:77: syncconfig] Error 1
  make[5]: *** [Makefile:616: syncconfig] Error 2
  make[4]: *** [Makefile:736: include/config/auto.conf.cmd] Error 2
  make[3]: *** [Makefile:24: build_dir/target-mipsel-openwrt-linux-musl_musl/linux-ramips_mt7620/linux-5.15.62/.modules] Error 2
  make[2]: *** [Makefile:11: compile] Error 2
  time: target/linux/compile#30.09#11.30#37.92

Signed-off-by: Petr Štetiar <ynezz@true.cz>
(cherry picked from commit f4ca4187cde01a3e412f10657bec0790d3a4cd94)