ARM: OMAP4+: Allow kexec on SMP variants

Kexec needs omap4_cpu_kill, otherwise kexec will produce on SMP:

kexec_load failed: Invalid argument
Acked-by: Santosh Shilimkar <ssantosh@kernel.org>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

arch/arm/mach-omap2/common.h

@@ -272,6 +272,7 @@ extern void omap_auxcoreboot_addr(u32 cpu_addr);
 extern u32 omap_read_auxcoreboot0(void);
 
 extern void omap4_cpu_die(unsigned int cpu);
+extern int omap4_cpu_kill(unsigned int cpu);
 
 extern const struct smp_operations omap4_smp_ops;
 

arch/arm/mach-omap2/omap-hotplug.c

@@ -64,3 +64,9 @@ void omap4_cpu_die(unsigned int cpu)
 		pr_debug("CPU%u: spurious wakeup call\n", cpu);
 	}
 }
+
+/* Needed by kexec and platform_can_cpu_hotplug() */
+int omap4_cpu_kill(unsigned int cpu)
+{
+	return 1;
+}