powerpc: export debug registers save function for KVM

KVM need this function when switching from vcpu to user-space
thread. My subsequent patch will use this function.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Acked-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Scott Wood <scottwood@freescale.com>
diff --git a/arch/powerpc/include/asm/switch_to.h b/arch/powerpc/include/asm/switch_to.h
index 2be5618..9ee1261 100644
--- a/arch/powerpc/include/asm/switch_to.h
+++ b/arch/powerpc/include/asm/switch_to.h
@@ -35,6 +35,7 @@
 extern void enable_kernel_spe(void);
 extern void giveup_spe(struct task_struct *);
 extern void load_up_spe(struct task_struct *);
+extern void switch_booke_debug_regs(struct thread_struct *new_thread);
 
 #ifndef CONFIG_SMP
 extern void discard_lazy_cpu_state(void);