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

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

  followings||following

While we are here, add a missing colon in the boilerplate in DT binding
documents.  The "you SoC" in allwinner,sunxi-pinctrl.txt was fixed as
well.

I reworded "as the followings:" to "as follows:" for
drivers/usb/gadget/udc/renesas_usb3.c.

Link: http://lkml.kernel.org/r/1481573103-11329-32-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/isdn/hardware/eicon/debug.c

@@ -2049,7 +2049,7 @@ static int diva_dbg_cmp_key(const char *ref, const char *key) {
 /*
   In case trace filter starts with "C" character then
   all following characters are interpreted as command.
-  Followings commands are available:
+  Following commands are available:
   - single, trace single call at time, independent from CPN/CiPN
 */
 static int diva_mnt_cmp_nmbr(const char *nmbr) {