media: cec: move driver for TDA9950 from drm/i2c

Move the driver for NXP TDA9950 / CEC part of TDA998x together to
drivers/media/i2c, close to other CEC drivers. Specify 'default
DRM_I2C_NXP_TDA998X' in order to simplify migration from old config
files as the Kconfig name has been changed to follow media/cec style.

Acked-by: Hans Verkuil <hverkuil@xs4all.nl>
Link: https://patchwork.freedesktop.org/patch/msgid/20250113-drm-move-tda998x-v3-2-214e0682a5e4@linaro.org


Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>