drm/bridge: correct DRM_BRIDGE_OP_EDID documentation

While the commit d807ad80 ("drm/bridge: add ->edid_read hook and
drm_bridge_edid_read()") and the commit 27b8f91c ("drm/bridge:
remove ->get_edid callback") replaced ->get_edid() callback with the
->edid_read(), they failed to update documentation. Fix the drm_bridge
docs to point to edid_read().

Fixes: 27b8f91c ("drm/bridge: remove ->get_edid callback")
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240310-drm-bridge-fix-docs-v1-1-70d3d741cb7a@linaro.org