drm/bridge: fix kdoc syntax

drm/bridge: fix kdoc syntax

Use the correct kdoc syntax for bullet list.

Fixes kdoc error and warning:

  Documentation/gpu/drm-kms-helpers:197: ./drivers/gpu/drm/drm_bridge.c:1519: ERROR: Unexpected indentation. [docutils]
  Documentation/gpu/drm-kms-helpers:197: ./drivers/gpu/drm/drm_bridge.c:1521: WARNING: Block quote ends without a blank line; unexpected unindent. [docutils]

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202512302319.1PGGt3CN-lkp@intel.com/
Fixes: 9da0e06abda8 ("drm/bridge: deprecate of_drm_find_bridge()")
Reviewed-by: Nicolas Frattaroli <nicolas.frattaroli@collabora.com>
Link: https://patch.msgid.link/20251231-drm-bridge-alloc-getput-drm_of_find_bridge-kdoc-fix-v1-1-193a03f0609c@bootlin.com
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>