ARM: kexec: record parent context registers for non-crash CPUs

How we got to machine_crash_nonpanic_core() (iow, from an IPI, etc) is
not interesting for debugging a crash.  The more interesting context
is the parent context prior to the IPI being received.

Record the parent context register state rather than the register state
in machine_crash_nonpanic_core(), which is more relevant to the failing
condition.
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

arch/arm/kernel/machine_kexec.c

@@ -83,7 +83,7 @@ void machine_crash_nonpanic_core(void *unused)
 {
 	struct pt_regs regs;
 
-	crash_setup_regs(&regs, NULL);
+	crash_setup_regs(&regs, get_irq_regs());
 	printk(KERN_DEBUG "CPU %u will stop doing anything useful since another CPU has crashed\n",
 	       smp_processor_id());
 	crash_save_cpu(&regs, smp_processor_id());