arm64: irqstat: Get rid of duplicated declaration

irq_cpustat_t is exactly the same as the asm-generic one. Define
ack_bad_irq so the generic header does not emit the generic version of it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201113141733.392015387@linutronix.de

arch/arm64/include/asm/hardirq.h

@@ -13,11 +13,8 @@
 #include <asm/kvm_arm.h>
 #include <asm/sysreg.h>
 
-typedef struct {
-	unsigned int __softirq_pending;
-} ____cacheline_aligned irq_cpustat_t;
-
-#include <linux/irq_cpustat.h>	/* Standard mappings for irq_cpustat_t above */
+#define ack_bad_irq ack_bad_irq
+#include <asm-generic/hardirq.h>
 
 #define __ARCH_IRQ_EXIT_IRQS_DISABLED	1