em28xx-dvb: remove some left over

Gcc 6.1 warns about an unused table:

drivers/media/usb/em28xx/em28xx-dvb.c:907:38: warning: 'pctv_461e_m88ds3103_config' defined but not used [-Wunused-const-variable=]
 static const struct m88ds3103_config pctv_461e_m88ds3103_config = {
                                      ^~~~~~~~~~~~~~~~~~~~~~~~~~

That's a left over of patch 76b91be3 ('em28xx: PCTV 461e use I2C
client for demod and SEC').

Remove the dead code.

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