drm/bridge: it6505: add I2C functionality on AUX

DisplayPort AUX protocol supports I2C transport which is capable of
reading EDID or supports MCCS.

In drm_dp_helper, drm_dp_i2c_xfer() packs I2C requests into a
sequence of AUX requests.
it6505_aux_i2c_operation() is implemented to match drm_dp_i2c_xfer()
operactions.
it6505_aux_i2c_transfer() adds I2C functionality
for it6505_aux_transfer().

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Hermes Wu <hermes.wu@ite.com.tw>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20241230-v7-upstream-v7-10-e0fdd4844703@ite.corp-partner.google.com