target/arm: Set ISSIs16Bit in make_issinfo

During the conversion to decodetree, the setting of
ISSIs16Bit got lost. This causes the guest os to
incorrectly adjust trapping memory operations.

Backports commit 1a1fbc6cbb34c26d43d8360c66c1d21681af14a9 from qemu

qemu/target/arm/translate.c

@@ -8819,6 +8819,9 @@ static ISSInfo make_issinfo(DisasContext *s, int rd, bool p, bool w)
     /* ISS not valid if writeback */
     if (p && !w) {
         ret = rd;
+        if (s->base.pc_next - s->pc_curr == 2) {
+            ret |= ISSIs16Bit;
+        }
     } else {
         ret = ISSInvalid;
     }