The variable sysctl_panic_on_stackoverflow is used in
arch/parisc/kernel/irq.c and arch/x86/kernel/irq_32.c, but the sysctl file
interface panic_on_stackoverflow only exists on x86.

Add sysctl file interface panic_on_stackoverflow for parisc
Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>