arch-arm: Fix missing Request allocation

This patch is fixing a missing allocation for a Request buffer
in the Stage2Translation class.

Change-Id: I9ce7b85d3527c5b3cc895eb83e9a39641793b0bd
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/11095
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>

src/arch/arm/stage2_mmu.cc

@@ -113,6 +113,7 @@ Stage2MMU::Stage2Translation::Stage2Translation(Stage2MMU &_parent,
     : data(_data), numBytes(0), event(_event), parent(_parent), oVAddr(_oVAddr),
     fault(NoFault)
 {
+    req = std::make_shared<Request>();
 }
 
 void