MLK-19485 drm/bridge: it6263: Change LVDS I2C device to be dummy

The it6263 bridge contains two I2C devices on the same I2C bus
to control HDMI and LVDS modules respectively.  However, they
have different I2C addresses.  Thus, one of the two devices should
be registered as dummy device and bound with dummy driver.  This
is what the helper i2c_new_dummy() is designed for.  The HDMI I2C
device is normally registered as a real I2C device and bound with
a real driver, so the LVDS I2C device should be dummy.

This patch fixes the issue to access the LVDS I2C device's sys nodes,
like /sys/kernel/debug/regmap/2-0033/name.

Signed-off-by: Liu Ying <victor.liu@nxp.com>