iommu: Fix a check in iommu_check_bind_data()

iommu: Fix a check in iommu_check_bind_data()

The "data->flags" variable is a u64 so if one of the high 32 bits is
set the original code will allow it, but it should be rejected.  The
fix is to declare "mask" as a u64 instead of a u32.

Fixes: 68457ee67e6a ("iommu/uapi: Handle data and argsz filled by users")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20201103101623.GA1127762@mwanda
Signed-off-by: Joerg Roedel <jroedel@suse.de>