livepatch: samples: fix usage example comments

Fix a few typos in the livepatch-sample.c usage example comments and add
some whitespace to make the comments a little more legible.

Reported-by: Udo Seidel <udoseidel@gmx.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>