V4L/DVB (5618): Cx88: Drop the generic i2c client from cx88-vp3054-i2c

Drop the generic client declared in cx88-vp3054-i2c: it's not used
anywhere. This shrinks cx88-vp3054-i2c.o by 29% on x86_64. Unless it
was there for later use?

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>