cpu,arch-arm: Initialise data members

The value that is not initialized has a bogus value that manifests when
using some debug-flags what makes the usage of tracediff a bit more
challenging.

In addition, while debugging with other techniques, it introduces the
problem of understanding if the value of a field is 'intended' or just
an effect of the lack of initialisation.

Change-Id: Ied88caa77479c6f1d5166d80d1a1a057503cb106
Signed-off-by: Giacomo Gabrielli <giacomo.gabrielli@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/13125
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>

src/cpu/checker/cpu.cc

@@ -67,7 +67,9 @@ CheckerCPU::init()
 
 CheckerCPU::CheckerCPU(Params *p)
     : BaseCPU(p, true), systemPtr(NULL), icachePort(NULL), dcachePort(NULL),
-      tc(NULL), thread(NULL)
+      tc(NULL), thread(NULL),
+      unverifiedReq(nullptr),
+      unverifiedMemData(nullptr)
 {
     curStaticInst = NULL;
     curMacroStaticInst = NULL;