klp: remove CONFIG_LIVEPATCH dependency from klp headers

There is no need for livepatch.h (generic and arch-specific) to depend
on CONFIG_LIVEPATCH. Remove that superfluous dependency.

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