powerpc/crash: Fix non-smp kexec preparation

In non-smp configurations, crash_kexec_prepare is never called in
the crash shutdown path. One result of this is that the crashing_cpu
variable is never set, preventing crash_save_cpu from storing the
NT_PRSTATUS elf note in the core dump.

Fixes: c725505 ("powerpc/crash: save cpu register data in crash_smp_send_stop()")
Signed-off-by: Eddie James <[email protected]>
Reviewed-by: Hari Bathini <[email protected]>
Signed-off-by: Madhavan Srinivasan <[email protected]>
Link: https://patch.msgid.link/[email protected]

Author: Eddie James

arch/powerpc/kexec/crash.c

@@ -359,7 +359,10 @@ void default_machine_crash_shutdown(struct pt_regs *regs)
 	if (TRAP(regs) == INTERRUPT_SYSTEM_RESET)
 		is_via_system_reset = 1;
 
-	crash_smp_send_stop();
+	if (IS_ENABLED(CONFIG_SMP))
+		crash_smp_send_stop();
+	else
+		crash_kexec_prepare();
 
 	crash_save_cpu(regs, crashing_cpu);