perf tools: Fix LLVM download hint link

http://llvm.org/apt returns 404, it has moved to https://apt.llvm.org/

Signed-off-by: James Clark <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: [e-mail]
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/llvm-utils.c

···
 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 "     \tdebian/ubuntu:\n"
-"     \t\thttp://llvm.org/apt\n\n"
+"     \t\thttps://apt.llvm.org/\n\n"
 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"