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>

drivers/media/usb/tm6000/tm6000-input.c

@@ -438,7 +438,7 @@ int tm6000_ir_init(struct tm6000_core *dev)
 
 	/* input setup */
 	rc->allowed_protocols = RC_BIT_RC5 | RC_BIT_NEC;
-	/* Neded, in order to support NEC remotes with 24 or 32 bits */
+	/* Needed, in order to support NEC remotes with 24 or 32 bits */
 	rc->scancode_mask = 0xffff;
 	rc->priv = ir;
 	rc->change_protocol = tm6000_ir_change_protocol;