scripts/config: fix double-quotes un-escaping

When reporting a string value, only the first double-quote was
un-escaped. We need to un-escape all escaped double-quotes.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Michal Marek <mmarek@suse.cz>

scripts/config

@@ -128,7 +128,7 @@ while [ "$1" != "" ] ; do
 				V="${V/#CONFIG_$ARG=/}"
 				V="${V/#\"/}"
 				V="${V/%\"/}"
-				V="${V/\\\"/\"}"
+				V="${V//\\\"/\"}"
 				echo "${V}"
 			fi
 		fi