Building linux-6.6.y with clang-11 has been broken for almost a year:
  ClangBuiltLinux/linux#2069
There has never been a report about this breakage as far as I can tell,
so it is likely nobody is actually using clang-11 on 6.6. While the
other trees are working fine at the moment, there is not much coverage
gained from having these builds going, so just remove them all.
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Signed-off-by: Nathan Chancellor <nathan@kernel.org>