ARM: 9232/1: Replace this_cpu_* with raw_cpu_* in handle_bad_stack()

The hardware automatically disable the IRQ interrupt before jumping to the
interrupt or exception vector. Therefore, the preempt_disable() operation
in this_cpu_read() after macro expansion is unnecessary. In fact, function
this_cpu_read() may trigger scheduling, see pseudocode below.

Pseudocode of this_cpu_read(xx):
preempt_disable_notrace();
raw_cpu_read(xx);
if (unlikely(__preempt_count_dec_and_test()))
	__preempt_schedule_notrace();

Therefore, use raw_cpu_* instead of this_cpu_* to eliminate potential
hazards. At the very least, it reduces a few lines of assembly code.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>