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: d905738 ("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>

Author: Dan Carpenter

drivers/iommu/iommu.c

@@ -2071,7 +2071,7 @@ EXPORT_SYMBOL_GPL(iommu_uapi_cache_invalidate);
 
 static int iommu_check_bind_data(struct iommu_gpasid_bind_data *data)
 {
-	u32 mask;
+	u64 mask;
 	int i;
 
 	if (data->version != IOMMU_GPASID_BIND_VERSION_1)