ec/curve448/curve448.c: fix undefined behaviour sanitizer failure.
@@ -579,7 +579,7 @@ static int recode_wnaf(struct smvt_control *control,
assert(position >= 0);
if (odd & (1 << (table_bits + 1)))
delta -= (1 << (table_bits + 1));
- current -= delta << pos;
+ current -= delta * (1 << pos);
control[position].power = pos + 16 * (w - 1);
control[position].addend = delta;
position--;
