scripts/spelling.txt: add "neded" pattern and fix typo instances

Fix typos and add the following to the scripts/spelling.txt:

  neded||needed

While we are here, fix the "overriden", "wont", and "etc" in the same
hunk in drivers/media/usb/tm6000/tm6000-input.c.

Link: http://lkml.kernel.org/r/1481573103-11329-14-git-send-email-yamada.masahiro@socionext.com


Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>