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

Since commit 84af7a6194e4 ("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>
diff --git a/net/mac802154/Kconfig b/net/mac802154/Kconfig
index 742624e..901167b 100644
--- a/net/mac802154/Kconfig
+++ b/net/mac802154/Kconfig
@@ -8,7 +8,7 @@
 	select CRYPTO_CCM
 	select CRYPTO_CTR
 	select CRYPTO_AES
-	---help---
+	help
 	  This option enables the hardware independent IEEE 802.15.4
 	  networking stack for SoftMAC devices (the ones implementing
 	  only PHY level of IEEE 802.15.4 standard).