[media] smiapp-pll: include linux/device.h in smiapp-pll.c, not in smiapp-pll.h

struct device has a forward declaration in the header already. The header is
only needed in the .c file.

Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>