Big cleanup in config help and description

Redundant help texts (one which only repeats the description)
are deleted.

Descriptions and help texts are trimmed.

Some config options are moved, even across menus.

No config option _names_ are changed.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/networking/tftp.c b/networking/tftp.c
index ed86720..189364f 100644
--- a/networking/tftp.c
+++ b/networking/tftp.c
@@ -69,11 +69,9 @@
 //config:	  "blksize" and "tsize" options.
 //config:
 //config:config FEATURE_TFTP_PROGRESS_BAR
-//config:	bool "Enable tftp progress meter"
+//config:	bool "Enable progress bar"
 //config:	default y
 //config:	depends on TFTP && FEATURE_TFTP_BLOCKSIZE
-//config:	help
-//config:	  Show progress bar.
 //config:
 //config:config TFTP_DEBUG
 //config:	bool "Enable debug"