drm/bridge: analogix: remove unused struct 'bridge_init'

drm/bridge: analogix: remove unused struct 'bridge_init'

commit 6a1688ae8794 ("drm/bridge: ptn3460: Convert to I2C driver model")
has dropped all the users of the struct bridge_init from the
exynos_dp_core, while retaining unused structure definition.
Later on the driver was reworked and the definition migrated
to the analogix_dp driver. Remove unused struct bridge_init definition.

Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240520125551.11534-1-linux@treblig.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>