ltp: Update to 20210524

Remove patches accepted in this upstream release
* determinism.patch (45530792a, 01fefa08c)
* libswapon.patch (2b64c727f)
* 0001-open_posix_testsuite-generate-makefiles.sh-Avoid-inc.patch
  (f38172209)
* 0002-Makefile-Avoid-wildcard-determinism-issues.patch (edf60cf6a)
* 0003-syscalls-swapon-swapoff-Move-common-library-to-libs.patch
  (ac140ed58)

Removed (test rewritten to new API)
* 0007-Fix-test_proc_kill-hanging.patch

Signed-off-by: Petr Vorel <petr.vorel@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>