cpu/ rtc/ include/: Remove lingering references to CFG_CMD_* symbols.

Signed-off-by: Jon Loeliger <jdl@freescale.com>
diff --git a/rtc/max6900.c b/rtc/max6900.c
index 63f643c..c75a8e0 100644
--- a/rtc/max6900.c
+++ b/rtc/max6900.c
@@ -128,4 +128,4 @@
 {
 }
 
-#endif	/* CONFIG_RTC_MAX6900 && CFG_CMD_DATE */
+#endif