[media] xc5000: fix xc5000 suspend

After xc5000 stops working, it waits for 5 seconds, waiting
for a new usage. Only after that it goes to low power mode.

If a suspend event happens before that, a work queue will
remain active, with causes suspend to crash.

Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>