ARM: Support unaligned memory access.

Without this flag set, page-crossing requests were not split into two mem
request.

Depending on the alignment bit in the SCTLR, misaligned access could
raise a fault. However it seems unnecessary to implement that.

src/arch/arm/isa_traits.hh

@@ -113,7 +113,7 @@ namespace ArmISA
     const uint32_t HighVecs = 0xFFFF0000;
 
     // Memory accesses cannot be unaligned
-    const bool HasUnalignedMemAcc = false;
+    const bool HasUnalignedMemAcc = true;
 
     enum InterruptTypes
     {