V4L/DVB (3667b): cpia2: fix function prototype

Fix address space warning (from sparse):
drivers/media/video/cpia2/cpia2_core.c:2355:6: error: symbol 'cpia2_read' redeclared with different type (originally declared at drivers/media/video/cpia2/cpia2.h:458) - incompatible argument 2 (different address spaces)

Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>