s390/irq: use assignment instead of cast

Change struct ext_code to contain a union which allows to simply
assign the int_code instead of using a cast.

In order to keep the patch small the anonymous union is embedded
within the existing struct instead of changing the struct ext_code to
a union.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/include/asm/irq.h

@@ -81,8 +81,13 @@ static __always_inline void inc_irq_stat(enum interruption_class irq)
 }
 
 struct ext_code {
-	unsigned short subcode;
-	unsigned short code;
+	union {
+		struct {
+			unsigned short subcode;
+			unsigned short code;
+		};
+		unsigned int int_code;
+	};
 };
 
 typedef void (*ext_int_handler_t)(struct ext_code, unsigned int, unsigned long);

arch/s390/kernel/irq.c

@@ -342,7 +342,7 @@ static irqreturn_t do_ext_interrupt(int irq, void *dummy)
 	struct ext_int_info *p;
 	int index;
 
-	ext_code = *(struct ext_code *) &regs->int_code;
+	ext_code.int_code = regs->int_code;
 	if (ext_code.code != EXT_IRQ_CLK_COMP)
 		set_cpu_flag(CIF_NOHZ_DELAY);