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

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

  applys||applies

The "applyes" in drivers/video/fbdev/aty/radeon_monitor.c is a different
pattern but it was fixed in this commit.  The "This functions" in the
same line was fixed as well.

Link: http://lkml.kernel.org/r/1481573103-11329-24-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>