drm/display: bridge-connector: remove unused variable assignment

drm/display: bridge-connector: remove unused variable assignment

The 'bridge' pointer started being assigned and used within this 'if' scope
in commit 0beba3f9d366 ("drm/bridge: connector: add support for HDMI codec
framework").

After that, commit 5d04b4188959 ("drm/bridge: split HDMI Audio from
DRM_BRIDGE_OP_HDMI") removed the code dereferencing it from the same 'if'
scope, but did not remove the assignment.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20250808-drm-bridge-alloc-getput-for_each_bridge-v2-2-edb6ee81edf1@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>