MIPS: fix build breakage due to r9607, faster slow asserts.

BUG=
TEST=

Review URL: http://codereview.chromium.org/8283025
Patch from Paul Lind <plind44@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9616 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/mips/code-stubs-mips.cc

@@ -6889,7 +6889,7 @@ void DirectCEntryStub::Generate(MacroAssembler* masm) {
   // The saved ra is after the reserved stack space for the 4 args.
   __ lw(t9, MemOperand(sp, kCArgsSlotsSize));
 
-  if (FLAG_debug_code && EnableSlowAsserts()) {
+  if (FLAG_debug_code && FLAG_enable_slow_asserts) {
     // In case of an error the return address may point to a memory area
     // filled with kZapValue by the GC.
     // Dereference the address and check for this.