MIPS: Lemote 2F: Suspend CS5536 MFGPT Timer

Before putting the Loongson 2F into wait mode, suspend the MFGPT Timer and
after wake-up resume it.  This may save some power.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/706/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>