Add require_alignment tag to store_func

Will be used similarly as in load_func.

riscv/mmu.h

@@ -147,7 +147,7 @@ public:
 
   // template for functions that store an aligned value to memory
   #define store_func(type, prefix, xlate_flags) \
-    void prefix##_##type(reg_t addr, type##_t val, bool actually_store=true) {   \
+    void prefix##_##type(reg_t addr, type##_t val, bool actually_store=true, bool require_alignment=false) { \
       if (unlikely(addr & (sizeof(type##_t)-1))) \
         return misaligned_store(addr, val, sizeof(type##_t), xlate_flags); \
       reg_t vpn = addr >> PGSHIFT; \