powerpc: Unify the 32 and 64 bit idle loops

This unifies the 32-bit (ARCH=ppc and ARCH=powerpc) and 64-bit idle
loops.  It brings over the concept of having a ppc_md.power_save
function from 32-bit to ARCH=powerpc, which lets us get rid of
native_idle().  With this we will also be able to simplify the idle
handling for pSeries and cell.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/include/asm-ppc/machdep.h b/include/asm-ppc/machdep.h
index a3e8a45..ebbef64e 100644
--- a/include/asm-ppc/machdep.h
+++ b/include/asm-ppc/machdep.h
@@ -44,7 +44,7 @@
 	void		(*power_off)(void);
 	void		(*halt)(void);
 
-	void		(*idle)(void);
+	void		(*idle_loop)(void);
 	void		(*power_save)(void);
 
 	long		(*time_init)(void); /* Optional, may be NULL */