[media] media: davinci: vpif_display: move the freeing of irq and global variables to remove()

Ideally the freeing of irq's and the global variables needs to be
done in the remove() rather than module_exit(), this patch moves
the freeing up of irq's and freeing the memory allocated to channel
objects to remove() callback of struct platform_driver.

Signed-off-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>