[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>
diff --git a/arch/arm/mach-ixp2000/core.c b/arch/arm/mach-ixp2000/core.c
index 594b4c4..781d10a 100644
--- a/arch/arm/mach-ixp2000/core.c
+++ b/arch/arm/mach-ixp2000/core.c
@@ -317,7 +317,7 @@
 	for (i = 0; i <= 7; i++) {
 		if (status & (1<<i)) {
 			desc = irq_desc + i + IRQ_IXP2000_GPIO0;
-			desc->handle(i + IRQ_IXP2000_GPIO0, desc, regs);
+			desc_handle_irq(i + IRQ_IXP2000_GPIO0, desc, regs);
 		}
 	}
 }