[POWERPC] powermac: Fix warning in time.c

arch/powerpc/platforms/powermac/time.c:88: warning: 'to_rtc_time' defined but not used

This fixes the warning by making the relevant code depend on the
users.
Signed-off-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/platforms/powermac/time.c

@@ -84,12 +84,14 @@ long __init pmac_time_init(void)
 	return delta;
 }
 
+#if defined(CONFIG_ADB_CUDA) || defined(CONFIG_ADB_PMU)
 static void to_rtc_time(unsigned long now, struct rtc_time *tm)
 {
 	to_tm(now, tm);
 	tm->tm_year -= 1900;
 	tm->tm_mon -= 1;
 }
+#endif
 
 static unsigned long from_rtc_time(struct rtc_time *tm)
 {