input: drop empty comment blocks

Commit 1a59d1b8 ("treewide: Replace GPLv2 boilerplate/reference with
SPDX - rule 156") has left some empty comment blocks.

Remove them to save a few lines of code.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/26a2b905b259bfffaf2de5b26f2007b8606970ed.1664478665.git.christophe.jaillet@wanadoo.fr


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>