mfd: Fix twl-irq function declaration warnings

Fixes following sparse warnings for twl4030 and twl6030 irq files.

drivers/mfd/twl4030-irq.c:783:5: warning: symbol 'twl4030_init_irq' was not
declared. Should it be static?
drivers/mfd/twl4030-irq.c:863:5: warning: symbol 'twl4030_exit_irq' was not
declared. Should it be static?
drivers/mfd/twl4030-irq.c:873:5: warning: symbol 'twl4030_init_chip_irq' was
not declared. Should it be static?

drivers/mfd/twl6030-irq.c:226:5: warning: symbol 'twl6030_init_irq' was not
declared. Should it be static?
drivers/mfd/twl6030-irq.c:290:5: warning: symbol 'twl6030_exit_irq' was not
declared. Should it be static?

Signed-off-by: G, Manjunath Kondaiah <manjugk@ti.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Tony Lindgren <tony@atomide.com>
Cc: Nishanth Menon <nm@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/twl4030-irq.c b/drivers/mfd/twl4030-irq.c
index 381ab26..5d3a147 100644
--- a/drivers/mfd/twl4030-irq.c
+++ b/drivers/mfd/twl4030-irq.c
@@ -35,6 +35,7 @@
 
 #include <linux/i2c/twl.h>
 
+#include "twl-core.h"
 
 /*
  * TWL4030 IRQ handling has two stages in hardware, and thus in software.