Lift the use_lld restriction for PGO

It's unclear why use_lld was there, but it prevents PGO from working on
Mac and iOS because they don't use lld.

Bug: 1058979
Change-Id: I0c984db2abe3bc8ff59f068221dd6de1edbf887d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2101232
Reviewed-by: Nico Weber <thakis@chromium.org>
Commit-Queue: Yuke Liao <liaoyuke@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#750182}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 19d6a712220366b8593a3f16a303eaa06b3d32ba

config/compiler/pgo/BUILD.gn

@@ -13,8 +13,7 @@ config("pgo_instrumentation_flags") {
 
   # Only add flags when chrome_pgo_phase == 1, so that variables we would use
   # are not required to be defined when we're not actually using PGO.
-  if (chrome_pgo_phase == 1 && is_clang && use_lld && !is_nacl &&
-      is_a_target_toolchain) {
+  if (chrome_pgo_phase == 1 && is_clang && !is_nacl && is_a_target_toolchain) {
     cflags = [ "-fprofile-instr-generate" ]
     if (!is_win) {
       # Windows directly calls link.exe instead of the compiler driver when