[gn] Fix another ia32/x86 typo.

BUG=chromium:619503
TBR=jochen@chromium.org, vogelheim@chromium.org, dpranke@chromium.org, thakis@chromium.org
NOTRY=true

Review-Url: https://codereview.chromium.org/2072203002
Cr-Commit-Position: refs/heads/master@{#37052}

build_overrides/v8.gni

@@ -11,7 +11,7 @@ if (is_android) {
   import("//build/config/android/config.gni")
 }
 
-if (((v8_target_cpu == "ia32" ||
+if (((v8_target_cpu == "x86" ||
       v8_target_cpu == "x64" ||
       v8_target_cpu=="x87") &&
      (is_linux || is_mac)) ||