irq: csky: perform irqentry in entry code

In preparation for removing HANDLE_DOMAIN_IRQ_IRQENTRY, have arch/csky
perform all the irqentry accounting in its entry code. As arch/csky uses
GENERIC_IRQ_MULTI_HANDLER, we can use generic_handle_arch_irq() to do
so.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Guo Ren <guoren@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

arch/csky/kernel/irq.c

@@ -15,8 +15,3 @@ void __init init_IRQ(void)
 	setup_smp_ipi();
 #endif
 }
-
-asmlinkage void __irq_entry csky_do_IRQ(struct pt_regs *regs)
-{
-	handle_arch_irq(regs);
-}