docs: ABI: remove a meaningless UTF-8 character

Those two files have this character:
	- U+00ac ('¬'): NOT SIGN

at the end of the first line, apparently for no reason. Drop them.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/6cd3f0b47568fecb7889fd18d1d744c3aaf73866.1620744606.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>