More changes to the 5380 chips (January 26th, 2025)

Apparently the Trantor T130B SCSI controllers has a different way of calculating the timings and removed the scsi_bus_read() calls from the Current SCSI bus status port (Read Port+4).
Fixes NT using said controller as well as CD swapping while maintaining the correct accurate CD speed.

src/include/86box/scsi_ncr5380.h

@@ -74,6 +74,7 @@ typedef struct ncr_t {
     uint8_t output_data;
     uint8_t tx_data;
     uint8_t irq_state;
+    uint8_t isr_reg;
 
     uint8_t bus;