powerpc: Merge time.c and asm/time.h.

We now use the merged time.c for both 32-bit and 64-bit compilation
with ARCH=powerpc, and for ARCH=ppc64, but not for ARCH=ppc32.
This removes setup_default_decr (folds its function into time_init)
and moves wakeup_decrementer into time.c.  This also makes an
asm-powerpc/rtc.h.

Signed-off-by: Paul Mackerras <paulus@samba.org>

drivers/macintosh/via-pmu.c

@@ -588,17 +588,6 @@ pmu_get_model(void)
 	return pmu_kind;
 }
 
-#ifndef CONFIG_PPC64
-static inline void wakeup_decrementer(void)
-{
-	set_dec(tb_ticks_per_jiffy);
-	/* No currently-supported powerbook has a 601,
-	 * so use get_tbl, not native
-	 */
-	last_jiffy_stamp(0) = tb_last_stamp = get_tbl();
-}
-#endif
-
 static void pmu_set_server_mode(int server_mode)
 {
 	struct adb_request req;