MAINTAINERS: add new entry for ideapad-laptop

Signed-off-by: Ike Panhc <ike.pan@canonical.com>
Cc: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>