pcr: aflplusplus: fix typo
We need lld not lldb. Without lld we have:
[+] llvm_mode detected llvm 11+, enabling afl-lto LTO implementation
GNUmakefile.llvm:218: ld.lld not found, cannot enable LTO mode
Signed-off-by: Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org>