tcg: Create struct CPUTLB

Move all softmmu tlb data into this structure.  Arrange the
members so that we are able to place mask+table together and
at a smaller absolute offset from ENV.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

target/arm/translate-a64.c

@@ -14134,7 +14134,7 @@ static bool is_guarded_page(CPUARMState *env, DisasContext *s)
      * table entry even for that case.
      */
     return (tlb_hit(entry->addr_code, addr) &&
-            env->iotlb[mmu_idx][index].attrs.target_tlb_bit0);
+            env_tlb(env)->d[mmu_idx].iotlb[index].attrs.target_tlb_bit0);
 #endif
 }