mfd: Add WM1811 support

The WM1811 is mostly register compatible with the WM8994 and WM8958,
providing a high performance audio hub CODEC in a small form factor
suitable for ultra compact system designs.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Samuel Ortiz <sameo@linux.intel.com>

include/linux/mfd/wm8994/core.h

@@ -20,6 +20,7 @@
 enum wm8994_type {
 	WM8994 = 0,
 	WM8958 = 1,
+	WM1811 = 2,
 };
 
 struct regulator_dev;