UPSTREAM: arm: bury unused _TIF_RESTORE_SIGMASK

(cherry pick from commit 7d181b9626057c1f4fb4d231a3c176271782f459)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Bug: 9674955
Bug: 25773781
Change-Id: Iea50371c62a09612e1debde7dd59d5631450e5e5
1 file changed