[SeaBIOS] [PATCH] virtio-blk: Fix incorrect type conversion in virtio_blk_op()

[Xiaofei]

Fixes: a05af290bac5 ("virtio-blk: split large IO according to size_max")

When using spdk aio bdev driver, the qemu command line like this:
qemu-system-x86_64 \
    -chardev socket,id=char0,path=/tmp/vhost.0 \
    -device vhost-user-blk-pci,id=blk0,chardev=char0 \
    ...

Boot failure message as below:

e820 map has 7 items:
  0: 0000000000000000 - 000000000009fc00 = 1 RAM
  1: 000000000009fc00 - 00000000000a0000 = 2 RESERVED
  2: 00000000000f0000 - 0000000000100000 = 2 RESERVED
  3: 0000000000100000 - 000000007ffdd000 = 1 RAM
  4: 000000007ffdd000 - 0000000080000000 = 2 RESERVED
  5: 00000000feffc000 - 00000000ff000000 = 2 RESERVED
  6: 00000000fffc0000 - 0000000100000000 = 2 RESERVED
enter handle_19:
  NULL
Booting from Hard Disk...
Boot failed: could not read the boot disk

Signed-off-by: Xiaofei 
---
 src/hw/virtio-blk.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/hw/virtio-blk.c b/src/hw/virtio-blk.c
index 9b4a05a..ce3265e 100644
--- a/src/hw/virtio-blk.c
+++ b/src/hw/virtio-blk.c
@@ -92,7 +92,7 @@ virtio_blk_op(struct disk_op_s *op, int write)
     u16 blk_num_max;

if (vdrive->drive.blksize != 0 && max_io_size != 0)
-        blk_num_max = (u16)max_io_size / vdrive->drive.blksize;
+        blk_num_max = (u16)(max_io_size / vdrive->drive.blksize);
     else
         /* default blk_num_max if hardware doesnot advise a proper value */
         blk_num_max = 64;