Dyncom: Use size_t instead of int to store the instruction offsets in the instruction cache.

Fixes a few warnings.

src/core/arm/skyeye_common/armstate.h

@@ -230,7 +230,7 @@ public:
 
     // TODO(bunnei): Move this cache to a better place - it should be per codeset (likely per
     // process for our purposes), not per ARMul_State (which tracks CPU core state).
-    std::unordered_map<u32, int> instruction_cache;
+    std::unordered_map<u32, std::size_t> instruction_cache;
 
 private:
     void ResetMPCoreCP15Registers();