mips/cpu: Expose play_dead()'s prototype definition

Include <asm/smp.h> to make sure play_dead() matches its prototype going
forward.
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Link: https://lkml.kernel.org/r/20230216184249.ogaqsaykottpxtcb@trebleSigned-off-by: Josh Poimboeuf <jpoimboe@kernel.org>

arch/mips/cavium-octeon/smp.c

@@ -20,6 +20,7 @@
 #include <asm/mmu_context.h>
 #include <asm/time.h>
 #include <asm/setup.h>
+#include <asm/smp.h>
 
 #include <asm/octeon/octeon.h>
 

arch/mips/kernel/smp-bmips.c

@@ -54,6 +54,8 @@ static void bmips_set_reset_vec(int cpu, u32 val);
 
 #ifdef CONFIG_SMP
 
+#include <asm/smp.h>
+
 /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
 unsigned long bmips_smp_boot_sp;
 unsigned long bmips_smp_boot_gp;

arch/mips/kernel/smp-cps.c

@@ -20,6 +20,7 @@
 #include <asm/mipsregs.h>
 #include <asm/pm-cps.h>
 #include <asm/r4kcache.h>
+#include <asm/smp.h>
 #include <asm/smp-cps.h>
 #include <asm/time.h>
 #include <asm/uasm.h>

arch/mips/loongson64/smp.c

@@ -14,6 +14,7 @@
 #include <linux/cpufreq.h>
 #include <linux/kexec.h>
 #include <asm/processor.h>
+#include <asm/smp.h>
 #include <asm/time.h>
 #include <asm/tlbflush.h>
 #include <asm/cacheflush.h>