linux-user: Correct type for BLKSSZGET

The BLKSSZGET ioctl takes an argument which is a pointer to an int.
We were incorrectly declaring it to take a pointer to a long, which
meant that we would incorrectly write to memory which we should not
if the guest is a 64-bit architecture.

In particular, kpartx uses this ioctl to write to an int on the
stack, which tends to result in it crashing immediately.
Reported-by: NChanho Park <chanho61.park@samsung.com>
Reviewed-by: NLaurent Vivier <laurent@vivier.eu>
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>

linux-user/ioctls.h

@@ -76,7 +76,7 @@
      IOCTL(BLKFLSBUF, 0, TYPE_NULL)
      IOCTL(BLKRASET, 0, TYPE_INT)
      IOCTL(BLKRAGET, IOC_R, MK_PTR(TYPE_LONG))
-     IOCTL(BLKSSZGET, IOC_R, MK_PTR(TYPE_LONG))
+     IOCTL(BLKSSZGET, IOC_R, MK_PTR(TYPE_INT))
      IOCTL(BLKBSZGET, IOC_R, MK_PTR(TYPE_INT))
      IOCTL_SPECIAL(BLKPG, IOC_W, do_ioctl_blkpg,
                    MK_PTR(MK_STRUCT(STRUCT_blkpg_ioctl_arg)))