[PKT_SCHED]: fix typo on Kconfig

This is a trivial fix for a typo on Kconfig, where the Generic Random Early 
Detection algorithm is abbreviated as RED instead of GRED.
Signed-off-by: NLucas Correia Villa Real <lucasvr@gobolinux.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/Kconfig

@@ -185,7 +185,7 @@ config NET_SCH_GRED
 	depends on NET_SCHED
 	help
 	  Say Y here if you want to use the Generic Random Early Detection
-	  (RED) packet scheduling algorithm for some of your network devices
+	  (GRED) packet scheduling algorithm for some of your network devices
 	  (see the top of <file:net/sched/sch_red.c> for details and
 	  references about the algorithm).