mmc: fix "prev->state: 2 != TASK_RUNNING??" problem on SD/MMC card removal

Currently on SD/MMC card removal the system exhibits the following message (the platform is ARM Versatile):

    prev->state: 2 != TASK_RUNNING??
    mmcqd/762[CPU#0]: BUG in __schedule at linux-2.6/kernel/sched.c:3826

(akpm: someone tried to fix this, but it's still wrong)

Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>