message: Remove unnecessary casts
  Fixes clippy::cast_ref_to_mut
diff: @@ -571,12 +571,7 @@ impl<'a> ReadCtrl<'a> {
  ) {
  match (send_buff, recv_buff_spec) {
  (Some(send_buff), Some((recv_buff, mut write_len))) => {
  - // This is perfectly fine as we operate on two different datastructures inside one datastructure
  - // we can have two mutable references via the same wrapping datastructure
  - let ctrl_desc = unsafe {
  - let raw_ref = &mut *((send_buff as *const Buffer) as *mut Buffer);
  - raw_ref.get_ctrl_desc_mut().unwrap()
  - };
  + let ctrl_desc = send_buff.get_ctrl_desc_mut().unwrap();
  // This should read the descriptors inside the ctrl desc memory and update the memory
  // accordingly
  @@ -613,12 +608,7 @@ impl<'a> ReadCtrl<'a> {
  }
  }
  (Some(send_buff), None) => {
  - // This is perfectly fine as we operate on two different datastructures inside one datastructure
  - // we can have two mutable references via the same wrapping datastructure
  - let ctrl_desc = unsafe {
  - let raw_ref = &mut *((send_buff as *const Buffer) as *mut Buffer);
  - raw_ref.get_ctrl_desc_mut().unwrap()
  - };
  + let ctrl_desc = send_buff.get_ctrl_desc_mut().unwrap();
  // This should read the descriptors inside the ctrl desc memory and update the memory
  // accordingly
  @@ -638,12 +628,7 @@ impl<'a> ReadCtrl<'a> {
  }
  }
  (None, Some((recv_buff, mut write_len))) => {
  - // This is perfectly fine as we operate on two different datastructures inside one datastructure
  - // we can have two mutable references via the same wrapping datastructure
  - let ctrl_desc = unsafe {
  - let raw_ref = &mut *((recv_buff as *const Buffer) as *mut Buffer);
  - raw_ref.get_ctrl_desc_mut().unwrap()
  - };
  + let ctrl_desc = recv_buff.get_ctrl_desc_mut().unwrap();
  // This should read the descriptors inside the ctrl desc memory and update the memory
  // accordingly
  