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>

sound/ppc/snd_ps3.c

@@ -883,7 +883,7 @@ static void snd_ps3_audio_set_base_addr(uint64_t ioaddr_start)
 static void snd_ps3_audio_fixup(struct snd_ps3_card_info *card)
 {
 	/*
-	 * avsetting driver seems to never change the followings
+	 * avsetting driver seems to never change the following
 	 * so, init them here once
 	 */