BACKPORT: ARM: 7474/1: get rid of TIF_SYSCALL_RESTARTSYS

(cherry pick from commit 66285217)

just let do_work_pending() return 1 on normal local restarts and
-1 on those that had been caused by ERESTART_RESTARTBLOCK (and 0
is still "all done, sod off to userland now").  And let the asm
glue flip scno to restart_syscall(2) one if it got negative from
us...

[will: resolved conflicts with audit fixes]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Bug: 9674955
Bug: 25773781
Change-Id: I9dfff324249e930c6719c56ea9b27a37d36d277a