media: videobuf-dma-sg: number of pages should be unsigned long

As reported by smatch:

	drivers/media/v4l2-core/videobuf-dma-sg.c:245 videobuf_dma_init_kernel() warn: should 'nr_pages << 12' be a 64 bit type?

The printk should not be using %d for the number of pages.

After looking better, the real problem here is that the
number of pages should be long int.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>