ARM: 7471/1: Revert "7442/1: Revert "remove unused restart trampoline""

This reverts commit 3b0c0622.

We no longer require the restart trampoline for syscall restarting.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>