regmap: Add irq_base accessor to regmap_irq

Allows devices to discover their own interrupt without having to remember
it themselves.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/include/linux/regmap.h b/include/linux/regmap.h
index bd54cec..e7e8953 100644
--- a/include/linux/regmap.h
+++ b/include/linux/regmap.h
@@ -190,5 +190,6 @@
 			int irq_base, struct regmap_irq_chip *chip,
 			struct regmap_irq_chip_data **data);
 void regmap_del_irq_chip(int irq, struct regmap_irq_chip_data *data);
+int regmap_irq_chip_get_base(struct regmap_irq_chip_data *data);
 
 #endif