ublast_read_byteshifted_tdos() function

ublast_read_byteshifted_tdos - read TDO of byteshift writes Reads back from USB Blaster TDO bits, triggered by a 'byteshift write', ie. eight bits per received byte from USB interface, and store them in buffer. As the USB blaster stores the TDO bits in LSB (ie. first bit in (byte0, bit0), second bit in (byte0, bit1), ...), which is what we want to return, simply read bytes from USB interface and store them. Returns ERROR_OK if OK, ERROR_xxx if a read error occurred