mfd: sta2x11-mfd: Add regmap support

Signed-off-by: Davide Ciminaghi <ciminaghi@gnudd.com>
Acked-by: Alessandro Rubini <rubini@gnudd.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b280639..59359a7 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -1046,6 +1046,7 @@
 	bool "STA2X11 multi function device support"
 	depends on STA2X11
 	select MFD_CORE
+	select REGMAP_MMIO
 
 config MFD_SYSCON
 	bool "System Controller Register R/W Based on Regmap"