[ARM] 4838/1: Fix kexec for SA1100 machines

This patch sets KEXEC_CONTROL_MEMORY_LIMIT to (-1)UL. As the value is
compared with physical addresses TASK_SIZE makes no sense. Machines
where the RAM addresses start above TASK_SIZE kexecs eats all memory
and crashes the kernel without this patch.

Signed-off-by: Thomas Kunze <thommycheck@gmx.de>
Acked-by: Richard Purdie <rpurdie@rpsys.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>