esp.c: don't immediately raise INTR_BS if SCSI data needed in esp_do_dma()

esp.c: don't immediately raise INTR_BS if SCSI data needed in esp_do_dma()

In the case when more data is requested from the SCSI layer during a DMA data
transfer from a device, don't immediately fall through to the TC check logic.
Otherwise when TC is zero INTR_BS will be raised immediately rather than when
the next set of SCSI data is ready.

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: <20240112125420.514425-24-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>