[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-sa1100/irq.c b/arch/arm/mach-sa1100/irq.c
index cc349bc..c131a52 100644
--- a/arch/arm/mach-sa1100/irq.c
+++ b/arch/arm/mach-sa1100/irq.c
@@ -126,7 +126,7 @@
 		mask >>= 11;
 		do {
 			if (mask & 1)
-				desc->handle(irq, desc, regs);
+				desc_handle_irq(irq, desc, regs);
 			mask >>= 1;
 			irq++;
 			desc++;