drm/bridge: remove drm_bridge_get_edid() in favour of drm_bridge_edid_read()

All users of drm_bridge_get_edid() have been converted to use
drm_bridge_edid_read(). Remove drm_bridge_get_edid().

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/c51d50edddbe8816eaa63e6ccafa9f2354b506ba.1706038510.git.jani.nikula@intel.com