[ARM] 3024/1: Add cpu_v6_proc_fin

Patch from Tony Lindgren

Machine restart calls cpu_proc_fin() to clean and disable
cache, and turn off interrupts. This patch adds proper
cpu_v6_proc_fin.

Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>