esp.c: process non-DMA FIFO writes in esp_do_nodma()

esp.c: process non-DMA FIFO writes in esp_do_nodma()

Currently any write to the ESP FIFO in the MESSAGE OUT or COMMAND phases will
manually raise the bus service interrupt. Instead of duplicating the interrupt
logic in esp_reg_write(), update esp_do_nodma() to correctly process incoming
FIFO data during the MESSAGE OUT and COMMAND phases. Part of this change is to
call esp_nodma_ti_dataout() from handle_ti() to ensure that the DATA OUT phase
FIFO transfer only occurs when executing a non-DMA TI command instead of for
each byte entering the FIFO.

One slight complication is that NextSTEP uses multiple TI commands to transfer
the CDB one byte at a time (as opposed to loading the FIFO and using a single
TI command), so it is necessary to determine the expected length of the SCSI
CDB being received. This is handled by the introduction of a new
esp_cdb_length() function which returns the expected SCSI CDB length based
upon the first command byte.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Helge Deller <deller@gmx.de>
Tested-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20240112125420.514425-67-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>