powerpc: Fix wrong divisor in usecs_to_cputime

Commit d57af9b (taskstats: use real microsecond granularity for CPU times)
renamed msecs_to_cputime to usecs_to_cputime, but failed to update all
numbers on the way.  This causes nonsensical cpu idle/iowait values to be
displayed in /proc/stat (the only user of usecs_to_cputime so far).

This also renames __cputime_msec_factor to __cputime_usec_factor, adapting
its value and using it directly in cputime_to_usecs instead of doing two
multiplications.

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Acked-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/cputime.h b/arch/powerpc/include/asm/cputime.h
index 1cf20bd..33a3580 100644
--- a/arch/powerpc/include/asm/cputime.h
+++ b/arch/powerpc/include/asm/cputime.h
@@ -126,11 +126,11 @@
 /*
  * Convert cputime <-> microseconds
  */
-extern u64 __cputime_msec_factor;
+extern u64 __cputime_usec_factor;
 
 static inline unsigned long cputime_to_usecs(const cputime_t ct)
 {
-	return mulhdu(ct, __cputime_msec_factor) * USEC_PER_MSEC;
+	return mulhdu(ct, __cputime_usec_factor);
 }
 
 static inline cputime_t usecs_to_cputime(const unsigned long us)
@@ -143,7 +143,7 @@
 	sec = us / 1000000;
 	if (ct) {
 		ct *= tb_ticks_per_sec;
-		do_div(ct, 1000);
+		do_div(ct, 1000000);
 	}
 	if (sec)
 		ct += (cputime_t) sec * tb_ticks_per_sec;