selinux: always fill AVC decision in avc_has_perm_noaudit()

In the Linux kernel, the following vulnerability has been resolved: selinux: always fill AVC decision in avc_has_perm_noaudit() avc_has_perm_noaudit() is documented to return a copy of the access decision in @avd, but its early return for an empty requested permission set leaves the buffer untouched. All callers pass an uninitialized stack variable and afterwards feed it to avc_audit(), and the inode hook even stores it in the per-task decision cache. Fill in a deny-all, audit-all decision, similar to avd_init(), so every caller receives a defined value at no cost on the hot path.

Where it's fixed