MIPS: smp-cps: Fix potentially uninitialised value of core

Turning on DEBUG in smp-cps.c, or compiling the kernel with
CONFIG_DYNAMIC_DEBUG enabled results the build error:

arch/mips/kernel/smp-cps.c: In function 'play_dead':
./include/linux/dynamic_debug.h:126:3: error: 'core' may be used
uninitialized in this function [-Werror=maybe-uninitialized]

Fix this by always initialising the variable.

Fixes: 0d2808f3 ("MIPS: smp-cps: Add support for CPU hotplug of MIPSr6 processors")
Signed-off-by: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/15848/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/smp-cps.c

@@ -422,13 +422,12 @@ void play_dead(void)
 	local_irq_disable();
 	idle_task_exit();
 	cpu = smp_processor_id();
+	core = cpu_data[cpu].core;
 	cpu_death = CPU_DEATH_POWER;
 
 	pr_debug("CPU%d going offline\n", cpu);
 
 	if (cpu_has_mipsmt || cpu_has_vp) {
-		core = cpu_data[cpu].core;
-
 		/* Look for another online VPE within the core */
 		for_each_online_cpu(cpu_death_sibling) {
 			if (cpu_data[cpu_death_sibling].core != core)