Add webpages' URL and summarize 3 lines.

CREDITS:
 - Summarize 3 lines into one.
 - Add webpage.

MAINTAINERS:
 - Add auxdisplay drivers/tree webpages.

Signed-off-by: Miguel Ojeda Sandonis <maxextreme@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>