powerpc: Fix some bugs in the new merged time code

I had the sense of the test for when to use the old 601-style RTC
registers inverted.  pmac_calibrate_decr and via_calibrate_decr
weren't setting ppc_tb_freq, on which all the further calculations
depended.  Lastly, update_gtod was losing the top 32 bits of
the new tb_to_xs value.

Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 7d406b7..3e72237 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -222,7 +222,7 @@
  * between updates.
  */
 static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
-			       unsigned int new_tb_to_xs)
+			       u64 new_tb_to_xs)
 {
 	unsigned temp_idx;
 	struct gettimeofday_vars *temp_varp;