[llvm-exegesis] Fix typo in f2334c5

This should have been in the original commit, but I somehow forgot to
run git add && git commit --amend --no-edit between making the change in
my editor, saving the file, and pushing the commit.

Author: boomanaiden154

llvm/tools/llvm-exegesis/lib/BenchmarkRunner.cpp

@@ -423,7 +423,7 @@ class SubProcessFunctionExecutorImpl
     assert(static_cast<int>(CurrentCPU) == CPUToUse &&
            "Expected current CPU to equal the CPU requested by the user");
 #else
-    exit(ChildProcessExChildProcessExitCodeE::SetCPUAffinityFailed));
+    exit(ChildProcessExitCodeE::SetCPUAffinityFailed);
 #endif // defined(__x86_64__) && defined(SYS_getcpu)
   }