vfio/type1: fix unmap all on ILP32

Some ILP32 architectures support mapping a 32-bit vaddr within a 64-bit
iova space.  The unmap-all code uses 32-bit SIZE_MAX as an upper bound on
the extent of the mappings within iova space, so mappings above 4G cannot
be found and unmapped.  Use U64_MAX instead, and use u64 for size variables.
This also fixes a static analysis bug found by the kernel test robot running
smatch for ILP32.

Fixes: 0f53afa1 ("vfio/type1: unmap cleanup")
Fixes: c1965099

 ("vfio/type1: implement unmap all")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Message-Id: <1614281102-230747-1-git-send-email-steven.sistare@oracle.com>
Link: https://lore.kernel.org/linux-mm/20210222141043.GW2222@kadam


Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>