V4L/DVB (6572): dvb-usb/vp702x.c: cleanups

This patch contains the following cleanups:
- make the needlessly global vp702x_usb_out_op() static
- #if 0 the unused vp702x_power_ctrl()

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>