rtc: ds1337: drop "SYS" from config variables

There is some inconsistency between uses of CONFIG_RTC_DS13xx and
CONFIG_SYS_RTC_DS13xx. Address this by dropping the "SYS" from
these variables.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/UCP1020.h b/include/configs/UCP1020.h
index b2feccf..8579290 100644
--- a/include/configs/UCP1020.h
+++ b/include/configs/UCP1020.h
@@ -311,7 +311,7 @@
 #define CONFIG_SYS_SPD_BUS_NUM		1 /* For rom_loc and flash bank */
 
 #define CONFIG_RTC_DS1337
-#define CONFIG_SYS_RTC_DS1337_NOOSC
+#define CONFIG_RTC_DS1337_NOOSC
 #define CONFIG_SYS_I2C_RTC_ADDR		0x68
 #define CONFIG_SYS_I2C_PCA9557_ADDR	0x18
 #define CONFIG_SYS_I2C_NCT72_ADDR	0x4C