mmc: wbsd: initialize tasklets before requesting interrupt

With CONFIG_DEBUG_SHIRQ set we will get an interrupt as soon as we
allocate one.  Tasklets may be scheduled in the interrupt handler but they
will be initialized after the handler returns, causing a BUG() in
kernel/softirq.c when they run.

Should fix this Fedora bug report:
https://bugzilla.redhat.com/show_bug.cgi?id=449817

Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Acked-by: Pierre Ossman <drzeus@drzeus.cx>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>