[ARM] Wrap calls to descriptor handlers

This is part of Thomas Gleixner's generic IRQ patch, which converts
ARM to use the generic IRQ subsystem.  Here, we wrap calls to
desc->handler() in an inline function, desc_handle_irq().  This
reduces the size of Thomas' patch since the changes become more
localised.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-footbridge/isa-irq.c

@@ -95,7 +95,7 @@ isa_irq_handler(unsigned int irq, struct irqdesc *desc, struct pt_regs *regs)
 	}
 
 	desc = irq_desc + isa_irq;
-	desc->handle(isa_irq, desc, regs);
+	desc_handle_irq(isa_irq, desc, regs);
 }
 
 static struct irqaction irq_cascade = { .handler = no_action, .name = "cascade", };