mmc: sh_mmcif: ensure run-time suspend call is processed before suspend

With this post-v2.6.35 change applied:

commit a0a1a5fd
Author: Tejun Heo <tj@kernel.org>
Date:   Tue Jun 29 10:07:12 2010 +0200
    workqueue: reimplement workqueue freeze using max_active

freeze_workqueues_begin() was introduced and workqueue now gets frozen
before device drivers suspend operations.

We have to ensure that run-time PM suspend operation completes before
system-wide suspend is started.

Signed-off-by: Teppei Kamijou <teppei.kamijou.yb@renesas.com>
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Chris Ball <cjb@laptop.org>