If the IR worker is not stopped before the removal of the cx88xx module,
an OOPS may occur, because the worker function cx88_ir_work gets called.
So stop the ir worker.
Signed-off-by: Marton Balint <cus@fazekas.hu>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>