kasan, sched/headers: Uninline kasan_enable/disable_current()

<linux/kasan.h> is a low level header that is included early
in affected kernel headers. But it includes <linux/sched.h>
which complicates the cleanup of sched.h dependencies.

But kasan.h has almost no need for sched.h: its only use of
scheduler functionality is in two inline functions which are
not used very frequently - so uninline kasan_enable_current()
and kasan_disable_current().

Also add a <linux/sched.h> dependency to a .c file that depended
on kasan.h including it.

This paves the way to remove the <linux/sched.h> include from kasan.h.

Acked-by: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Signed-off-by: Ingo Molnar <[email protected]>

lib/sbitmap.c

@@ -15,6 +15,7 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+#include <linux/sched.h>
 #include <linux/random.h>
 #include <linux/sbitmap.h>
 #include <linux/seq_file.h>