[media] m5mols: Convert to devm_request_irq()

Using the managed function the free_irq() calls can be removed from the
probe error path and the remove handler.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>