treewide: replace '---help---' in Kconfig files with 'help'

Since commit 84af7a6194 ("checkpatch: kconfig: prefer 'help' over
'---help---'"), the number of '---help---' has been gradually
decreasing, but there are still more than 2400 instances.

This commit finishes the conversion. While I touched the lines,
I also fixed the indentation.

There are a variety of indentation styles found.

  a) 4 spaces + '---help---'
  b) 7 spaces + '---help---'
  c) 8 spaces + '---help---'
  d) 1 space + 1 tab + '---help---'
  e) 1 tab + '---help---'    (correct indentation)
  f) 1 tab + 1 space + '---help---'
  g) 1 tab + 2 spaces + '---help---'

In order to convert all of them to 1 tab + 'help', I ran the
following commend:

  $ find . -name 'Kconfig*' | xargs sed -i 's/^[[:space:]]*---help---/\thelp/'

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

net/unix/Kconfig

@@ -5,7 +5,7 @@
 
 config UNIX
 	tristate "Unix domain sockets"
-	---help---
+	help
 	  If you say Y here, you will include support for Unix domain sockets;
 	  sockets are the standard Unix mechanism for establishing and
 	  accessing network connections.  Many commonly used programs such as
@@ -29,6 +29,6 @@ config UNIX_DIAG
 	tristate "UNIX: socket monitoring interface"
 	depends on UNIX
 	default n
-	---help---
+	help
 	  Support for UNIX socket monitoring interface used by the ss tool.
 	  If unsure, say Y.