[S390] Fix a lot of sparse warnings.

Most noteable part of this commit is the new local header file entry.h
which contains all the function declarations of functions that get only
called from asm code or are arch internal. That way we can avoid extern
declarations in C files.
This is more or less the same that was done for sparc64.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

drivers/s390/cio/cio.c

@@ -670,10 +670,14 @@ do_IRQ (struct pt_regs *regs)
 			continue;
 		}
 		sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
-		if (sch)
-			spin_lock(sch->lock);
+		if (!sch) {
+			/* Clear pending interrupt condition. */
+			tsch(tpi_info->schid, irb);
+			continue;
+		}
+		spin_lock(sch->lock);
 		/* Store interrupt response block to lowcore. */
-		if (tsch (tpi_info->schid, irb) == 0 && sch) {
+		if (tsch(tpi_info->schid, irb) == 0) {
 			/* Keep subchannel information word up to date. */
 			memcpy (&sch->schib.scsw, &irb->scsw,
 				sizeof (irb->scsw));
@@ -681,8 +685,7 @@ do_IRQ (struct pt_regs *regs)
 			if (sch->driver && sch->driver->irq)
 				sch->driver->irq(sch);
 		}
-		if (sch)
-			spin_unlock(sch->lock);
+		spin_unlock(sch->lock);
 		/*
 		 * Are more interrupts pending?
 		 * If so, the tpi instruction will update the lowcore
@@ -708,8 +711,9 @@ void *cio_get_console_priv(void)
 /*
  * busy wait for the next interrupt on the console
  */
-void
-wait_cons_dev (void)
+void wait_cons_dev(void)
+	__releases(console_subchannel.lock)
+	__acquires(console_subchannel.lock)
 {
 	unsigned long cr6      __attribute__ ((aligned (8)));
 	unsigned long save_cr6 __attribute__ ((aligned (8)));