media: cx88: fix two warnings

drivers/media/pci/cx88/cx88-alsa.c:295 cx88_alsa_dma_init() warn: argument 3 to %08lx specifier is cast from pointer
drivers/media/pci/cx88/cx88-alsa.c:669 snd_cx88_wm8775_volume_put() warn: potential negative subtraction from max '65535 - (32768 * left) / right'

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>