Fix compilation failure due to -Wunneeded-internal-declaration

Bug: 
Change-Id: I9a98cdb032821d7155bf536da1b66bbce90389cf
Reviewed-on: https://chromium-review.googlesource.com/807926Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Ivica Bogosavljevic <ivica.bogosavljevic@mips.com>
Cr-Commit-Position: refs/heads/master@{#49872}

src/strtod.cc

@@ -163,6 +163,7 @@ static bool DoubleStrtod(Vector<const char> trimmed,
   // therefore accurate.
   // Note that the ARM and MIPS simulators are compiled for 32bits. They
   // therefore exhibit the same problem.
+  USE(exact_powers_of_ten);
   USE(kMaxExactDoubleIntegerDecimalDigits);
   USE(kExactPowersOfTenSize);
   return false;