kcov: Remove kcov include from sched.h and move it to its users.

The recent addition of in_serving_softirq() to kconv.h results in
compile failure on PREEMPT_RT because it requires
task_struct::softirq_disable_cnt. This is not available if kconv.h is
included from sched.h.

It is not needed to include kconv.h from sched.h. All but the net/ user
already include the kconv header file.

Move the include of the kconv.h header from sched.h it its users.
Additionally include sched.h from kconv.h to ensure that everything
task_struct related is available.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Link: https://lkml.kernel.org/r/20210218173124.iy5iyqv3a4oia4vv@linutronix.de

drivers/usb/usbip/usbip_common.h

@@ -18,6 +18,7 @@
 #include <linux/usb.h>
 #include <linux/wait.h>
 #include <linux/sched/task.h>
+#include <linux/kcov.h>
 #include <uapi/linux/usbip.h>
 
 #undef pr_fmt

include/linux/kcov.h

@@ -2,6 +2,7 @@
 #ifndef _LINUX_KCOV_H
 #define _LINUX_KCOV_H
 
+#include <linux/sched.h>
 #include <uapi/linux/kcov.h>
 
 struct task_struct;

include/linux/sched.h

@@ -14,7 +14,6 @@
 #include <linux/pid.h>
 #include <linux/sem.h>
 #include <linux/shm.h>
-#include <linux/kcov.h>
 #include <linux/mutex.h>
 #include <linux/plist.h>
 #include <linux/hrtimer.h>

net/core/skbuff.c

@@ -60,6 +60,7 @@
 #include <linux/prefetch.h>
 #include <linux/if_vlan.h>
 #include <linux/mpls.h>
+#include <linux/kcov.h>
 
 #include <net/protocol.h>
 #include <net/dst.h>

net/mac80211/iface.c

@@ -15,6 +15,7 @@
 #include <linux/if_arp.h>
 #include <linux/netdevice.h>
 #include <linux/rtnetlink.h>
+#include <linux/kcov.h>
 #include <net/mac80211.h>
 #include <net/ieee80211_radiotap.h>
 #include "ieee80211_i.h"

net/mac80211/rx.c

@@ -17,6 +17,7 @@
 #include <linux/etherdevice.h>
 #include <linux/rcupdate.h>
 #include <linux/export.h>
+#include <linux/kcov.h>
 #include <linux/bitops.h>
 #include <net/mac80211.h>
 #include <net/ieee80211_radiotap.h>