[S390] irq: merge irq.c and s390_ext.c

Merge irq.c and s390_ext.c into irq.c. That way all external interrupt
related functions are together.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 5e8ead4..2d6228f 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -22,10 +22,10 @@
 #include <linux/cpu.h>
 #include <linux/kprobes.h>
 
-#include <asm/s390_ext.h>
 #include <asm/timer.h>
 #include <asm/irq_regs.h>
 #include <asm/cputime.h>
+#include <asm/irq.h>
 
 static DEFINE_PER_CPU(struct vtimer_queue, virt_cpu_timer);