RTC: rtc-cmos.c: Fix warning on MIPS

This patch fixes the following warning with RTC_LIB on MIPS:

drivers/rtc/rtc-cmos.c:697:2: warning: #warning Assuming 128 bytes of
RTC+NVRAM address space, not 64 bytes.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Arnaud Patard <apatard@mandriva.com>
Cc: linux-mips@linux-mips.org
Cc: rtc-linux@googlegroups.com
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Patchwork: http://patchwork.linux-mips.org/patch/570/
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>