powerpc: Provide dummy crash_shutdown_register

When kexec is disabled, the crash_shutdown_{un,}register
functions are not available in the kernel.
This provides dummy inline functions for those so that
the callers don't have to worry about it.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>

include/asm-powerpc/kexec.h

@@ -34,6 +34,8 @@
 #ifndef __ASSEMBLY__
 #include <linux/cpumask.h>
 
+typedef void (*crash_shutdown_t)(void);
+
 #ifdef CONFIG_KEXEC
 
 #ifdef __powerpc64__
@@ -123,7 +125,6 @@ struct pt_regs;
 extern void default_machine_kexec(struct kimage *image);
 extern int default_machine_kexec_prepare(struct kimage *image);
 extern void default_machine_crash_shutdown(struct pt_regs *regs);
-typedef void (*crash_shutdown_t)(void);
 extern int crash_shutdown_register(crash_shutdown_t handler);
 extern int crash_shutdown_unregister(crash_shutdown_t handler);
 
@@ -143,6 +144,16 @@ static inline int overlaps_crashkernel(unsigned long start, unsigned long size)
 
 static inline void reserve_crashkernel(void) { ; }
 
+static inline int crash_shutdown_register(crash_shutdown_t handler)
+{
+	return 0;
+}
+
+static inline int crash_shutdown_unregister(crash_shutdown_t handler)
+{
+	return 0;
+}
+
 #endif /* CONFIG_KEXEC */
 #endif /* ! __ASSEMBLY__ */
 #endif /* __KERNEL__ */