ANDROID: Incremental fs: Fix mislabeled __user ptrs

Found by sparse

Bug: 153174547
Test: make C=2 fs/incfs/incrementalfs.ko no errors, incfs_test pass
Signed-off-by: Paul Lawrence <paullawrence@google.com>
Change-Id: I9ff4f4f35975fe09936724488b96cd8bdeeb719e