Fix the definition of the syzygy_optimize variable in GN

Remove the 'symbol_level==2' condition as we can assume than an official build (without fast link) will have symbols.

R=dpranke@chromium.org
BUG=628056

Review-Url: https://codereview.chromium.org/2167793002
Cr-Commit-Position: refs/heads/master@{#406698}

build/config/compiler/compiler.gni

@@ -62,7 +62,7 @@ declare_args() {
   # Generate Syzygy optimized binaries. Syzygy optimize mode is a profile
   # guided optimization that reorders code for better locality.
   syzygy_optimize = is_win && target_cpu == "x86" && is_official_build &&
-                    !is_clang && !is_win_fastlink && symbol_level == 2
+                    !is_clang && !is_win_fastlink
 }
 
 declare_args() {