ARM: omap: remove references to disable_irq_lch

The disable_irq_lch method is never actually used, so there's not much
point it existing; remove it.

Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

include/linux/omap-dma.h

@@ -275,7 +275,6 @@ struct omap_dma_dev_attr {
 struct omap_system_dma_plat_info {
 	struct omap_dma_dev_attr *dma_attr;
 	u32 errata;
-	void (*disable_irq_lch)(int lch);
 	void (*show_dma_caps)(void);
 	void (*clear_lch_regs)(int lch);
 	void (*clear_dma)(int lch);