[PKT_SCHED]: Make sch_fifo.o available when CONFIG_NET_SCHED is not set.

Based on patch by Patrick McHardy.

Add a new option, NET_SCH_FIFO, which provides a simple fifo qdisc
without requiring CONFIG_NET_SCHED.

The d80211 stack needs a generic fifo qdisc for WME.  At present it
uses net/d80211/fifo_qdisc.c which is functionally equivalent to
sch_fifo.c.  This patch will allow the d80211 stack to remove
net/d80211/fifo_qdisc.c and use sch_fifo.c instead.
Signed-off-by: David Kimdon <david.kimdon@devicescape.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/Kconfig

@@ -6,6 +6,7 @@ menu "QoS and/or fair queueing"
 
 config NET_SCHED
 	bool "QoS and/or fair queueing"
+	select NET_SCH_FIFO
 	---help---
 	  When the kernel has several packets to send out over a network
 	  device, it has to decide which ones to send first, which ones to
@@ -40,6 +41,9 @@ config NET_SCHED
 	  The available schedulers are listed in the following questions; you
 	  can say Y to as many as you like. If unsure, say N now.
 
+config NET_SCH_FIFO
+	bool
+
 if NET_SCHED
 
 choice

net/sched/Makefile

@@ -4,7 +4,7 @@
 
 obj-y	:= sch_generic.o
 
-obj-$(CONFIG_NET_SCHED)		+= sch_api.o sch_fifo.o sch_blackhole.o
+obj-$(CONFIG_NET_SCHED)		+= sch_api.o sch_blackhole.o
 obj-$(CONFIG_NET_CLS)		+= cls_api.o
 obj-$(CONFIG_NET_CLS_ACT)	+= act_api.o
 obj-$(CONFIG_NET_ACT_POLICE)	+= act_police.o
@@ -14,6 +14,7 @@ obj-$(CONFIG_NET_ACT_MIRRED)	+= act_mirred.o
 obj-$(CONFIG_NET_ACT_IPT)	+= act_ipt.o
 obj-$(CONFIG_NET_ACT_PEDIT)	+= act_pedit.o
 obj-$(CONFIG_NET_ACT_SIMP)	+= act_simple.o
+obj-$(CONFIG_NET_SCH_FIFO)	+= sch_fifo.o
 obj-$(CONFIG_NET_SCH_CBQ)	+= sch_cbq.o
 obj-$(CONFIG_NET_SCH_HTB)	+= sch_htb.o
 obj-$(CONFIG_NET_SCH_HPFQ)	+= sch_hpfq.o