esp: remove transfer size check from DMA DATA IN and DATA OUT transfers

The transfer size check was originally added to prevent consecutive DMA TI
commands from causing an assert() due to an existing SCSI request being in
progress, but since the last set of updates [*] this is no longer required.

Remove the transfer size check from DMA DATA IN and DATA OUT transfers so
that issuing a DMA TI command when there is no data left to transfer does
not cause an assert() due to an existing SCSI request being in progress.

[*] See commits f3ace75be8..78d68f312a

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2415
Message-ID: <20240713224249.468084-1-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>

hw/scsi/esp.c

@@ -594,7 +594,7 @@ static void esp_do_dma(ESPState *s)
         if (!s->current_req) {
             return;
         }
-        if (s->async_len == 0 && esp_get_tc(s) && s->ti_size) {
+        if (s->async_len == 0 && esp_get_tc(s)) {
             /* Defer until data is available.  */
             return;
         }
@@ -647,7 +647,7 @@ static void esp_do_dma(ESPState *s)
         if (!s->current_req) {
             return;
         }
-        if (s->async_len == 0 && esp_get_tc(s) && s->ti_size) {
+        if (s->async_len == 0 && esp_get_tc(s)) {
             /* Defer until data is available.  */
             return;
         }