What happens if you skip step 2 here?:
```rust
To close communication it is mandatory to follow these steps in order:
1. Disable DMA streams for Tx and Rx in the DMA registers, if the streams are used.
2. Disable the SPI by following the SPI disable procedure.
3. Disable DMA Tx and Rx buffers by clearing the TXDMAEN and RXDMAEN bits in the 
SPI_CR2 register, if DMA Tx and/or DMA Rx are used.
```