style: eliminate equality tests with true and false

Using '== true' in a boolean expression is totally redundant,
and using '== false' is pretty verbose (and arguably less
readable in most cases) compared to '!'.

It's somewhat of a pet peeve, perhaps, but I had some time
waiting for some tests to run and decided to clean these up.

Unfortunately, SLICC appears not to have the '!' operator,
so I had to leave the '== false' tests in the SLICC code.

src/cpu/o3/inst_queue_impl.hh

@@ -1262,7 +1262,7 @@ InstructionQueue<Impl>::addToDependents(DynInstPtr &new_inst)
             // it be added to the dependency graph.
             if (src_reg >= numPhysRegs) {
                 continue;
-            } else if (regScoreboard[src_reg] == false) {
+            } else if (!regScoreboard[src_reg]) {
                 DPRINTF(IQ, "Instruction PC %s has src reg %i that "
                         "is being added to the dependency chain.\n",
                         new_inst->pcState(), src_reg);