mfd: Split wm8350 IRQ code into a separate file

In preparation for refactoring - it's over 700 lines of well-isolated
code and having it in a file by itself makes things more managable.

While we're at it make sure that we clean up the IRQ if we fail after
acquiring it on init.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index 2455857..75638ca 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -19,6 +19,7 @@
 wm831x-objs			:= wm831x-core.o wm831x-irq.o wm831x-otp.o
 obj-$(CONFIG_MFD_WM831X)	+= wm831x.o
 wm8350-objs			:= wm8350-core.o wm8350-regmap.o wm8350-gpio.o
+wm8350-objs			+= wm8350-irq.o
 obj-$(CONFIG_MFD_WM8350)	+= wm8350.o
 obj-$(CONFIG_MFD_WM8350_I2C)	+= wm8350-i2c.o