useless cast [`-Wuseless-cast`] warnings with gcc 9.5.0

[jeking3]

When building with gcc 9.5.0 and the flag -Wuseless-cast, the following warnings are given:

include/aws/common/array_list.inl:122:39: warning: useless cast to type ‘void*’ [-Wuseless-cast]
  122 |         aws_secure_zero((void *)list->data, list->current_size);

aws/common/math.inl:89:47: warning: useless cast to type ‘size_t’ {aka ‘long unsigned int’} [-Wuseless-cast]
   89 |     return (size_t)aws_mul_u64_saturating(a, b);
   
aws/common/math.inl:103:50: warning: useless cast to type ‘uint64_t*’ {aka ‘long unsigned int*’} [-Wuseless-cast]
  103 |     return aws_mul_u64_checked(a, b, (uint64_t *)r);

aws/common/math.inl:116:47: warning: useless cast to type ‘size_t’ {aka ‘long unsigned int’} [-Wuseless-cast]
  116 |     return (size_t)aws_add_u64_saturating(a, b);

aws/common/math.inl:130:50: warning: useless cast to type ‘uint64_t*’ {aka ‘long unsigned int*’} [-Wuseless-cast]
  130 |     return aws_add_u64_checked(a, b, (uint64_t *)r);
  
aws/common/math.inl:140:47: warning: useless cast to type ‘size_t’ {aka ‘long unsigned int’} [-Wuseless-cast]
  140 |     return (size_t)aws_sub_u64_saturating(a, b);
  
aws/common/math.inl:150:50: warning: useless cast to type ‘uint64_t*’ {aka ‘long unsigned int*’} [-Wuseless-cast]
  150 |     return aws_sub_u64_checked(a, b, (uint64_t *)r);