parisc: Remove bogus __IRQ_STAT macro

This is a leftover from a historical array based implementation and unused.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20201113141732.680780121@linutronix.de

arch/parisc/include/asm/hardirq.h

@@ -32,7 +32,6 @@ typedef struct {
 DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 
 #define __ARCH_IRQ_STAT
-#define __IRQ_STAT(cpu, member) (irq_stat[cpu].member)
 #define inc_irq_stat(member)	this_cpu_inc(irq_stat.member)
 #define __inc_irq_stat(member)	__this_cpu_inc(irq_stat.member)
 #define ack_bad_irq(irq) WARN(1, "unexpected IRQ trap at vector %02x\n", irq)