[FREELDR:ARCH] Fix minor bugs; condense XboxDiskInit() a bit (#8732)

- `AtaInit()` returns the number of detected ATA devices. Therefore,
  when iterating over them, go from index 0 to the count _minus_ 1,
  in `Pc98InitializeBootDevices()` and in `XboxDiskInit()`.

- Initialize `DiskDrive->Type` to `DRIVE_TYPE_HDD` for detected SCSI
  hard-disk drives in `pc98disk.c!InitScsiDrive()`.

- Rearrange `XboxDiskInit()` and reduce its indentation level.

boot/freeldr/freeldr/arch/i386/pc98/pc98disk.c

@@ -397,6 +397,7 @@ InitScsiDrive(
         DiskDrive->Geometry.Heads = RegsOut.b.dh;
         DiskDrive->Geometry.SectorsPerTrack = RegsOut.b.dl;
         DiskDrive->Geometry.BytesPerSector = RegsOut.w.bx;
+        DiskDrive->Type = DRIVE_TYPE_HDD;
     }
     /* Other devices */
     else if (ScsiParameters != 0)
@@ -675,7 +676,7 @@ Pc98InitializeBootDevices(VOID)
      * that cannot boot from a CD-ROM and has LBA limitations.
      */
     AtaInit(&IdeDetectedCount);
-    for (i = 0; i <= IdeDetectedCount; i++)
+    for (i = 0; i < IdeDetectedCount; i++)
     {
         DiskDrive = &Pc98DiskDrive[BiosHardDriveDriveNumber];
         if (InitIdeDrive(DiskDrive, i))

boot/freeldr/freeldr/arch/i386/xbox/xboxdisk.c

@@ -42,31 +42,28 @@ static
 VOID
 XboxDiskInit(VOID)
 {
-    UCHAR DetectedCount;
-    UCHAR UnitNumber;
-    PDEVICE_UNIT DeviceUnit = NULL;
+    UCHAR DetectedCount, UnitNumber;
 
     ASSERT(!AtaInitialized);
-
     AtaInitialized = TRUE;
 
     /* Find first HDD and CD */
     AtaInit(&DetectedCount);
-    for (UnitNumber = 0; UnitNumber <= DetectedCount; UnitNumber++)
+    for (UnitNumber = 0; UnitNumber < DetectedCount; UnitNumber++)
     {
-        DeviceUnit = AtaGetDevice(UnitNumber);
-        if (DeviceUnit)
+        PDEVICE_UNIT DeviceUnit = AtaGetDevice(UnitNumber);
+        if (!DeviceUnit)
+            continue;
+
+        if (DeviceUnit->Flags & ATA_DEVICE_ATAPI)
         {
-            if (DeviceUnit->Flags & ATA_DEVICE_ATAPI)
-            {
-                if (!CdDrive)
-                    CdDrive = DeviceUnit;
-            }
-            else
-            {
-                if (!HardDrive)
-                    HardDrive = DeviceUnit;
-            }
+            if (!CdDrive)
+                CdDrive = DeviceUnit;
+        }
+        else
+        {
+            if (!HardDrive)
+                HardDrive = DeviceUnit;
         }
     }
 }