llvm11: Update to 11.1.0 release

From: YUAN RUI via freebsd-ports <freebsd-ports_at_freebsd.org>
Date: Thu, 17 Jun 2021 11:16:27 UTC

llvm11: Update to 11.1.0 release

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=256668