drm: drm_connector.c: Adjust end of block comment

Add a new line with */ on the last line of a block comment to follow the
Linux kernel coding conventions.
Problem found by checkpatch.

Signed-off-by: Beatriz Martins de Carvalho <martinsdecarvalhobeatriz@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/59abdb2d65a643d5937e5773db684b926e8c9233.1618756333.git.martinsdecarvalhobeatriz@gmail.com