drm/i2c: tda998x: group connector functions and funcs together

Group the TDA998x connector functions and funcs structures together
before the encoder support, rather than scattered amongst the rest of
the file.  This keeps like code together.

Tested-by: Robin Murphy <robin.murphy@arm.com>
Tested-by: Jon Medhurst <tixy@linaro.org>
Acked-by: Jon Medhurst <tixy@linaro.org>
Tested-by: Jyri Sarha <jsarha@ti.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>