probe: cmsis-dap: use Transfer command for one-byte transfer

[kkitayam]

In current implementation, one-byte transfer is encoded with TransferBlock command. But, in case of one-byte transfer, it is better to use Transfer command to reduce USB packet size.

TransferBlock command with one-byte read consumes 5 bytes size. Transfer command with one-byte read consumes 4 bytes size. TransferBlock command with one-byte write consumes 9 bytes size. Transfer command with one-byte write consumes 8 bytes size.