Update devel/linux-ltp from 20200605 to 20260130 and switch the port to the OBS ltp-stable RPM build for SLE 15 SP7.
- Replace the old local/CentOS-style source setup with direct openSUSE stable binary and source RPM fetches.
- Add PKGNAMESUFFIX=-stable, refresh COMMENT/WWW, and move the Linux base from linux:c7 with extra libs to linux:rl9 with USE_LINUX=base.
- Regenerate distinfo for the new stable RPM artifacts.
- Refresh pkg-plist.amd64 to match the new upstream package layout, including major removals from the old conformance tree and additions under open_posix_testsuite, updated helper scripts, and renamed doc/license paths for ltp-stable.