mfd: Switch AB3100 to use MFD cells

This switches the AB3100 core driver to using MFD cells for
subdevices instead of spawning common platform devices.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index db51ea1..b3aedaa 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -444,6 +444,7 @@
 config AB3100_CORE
 	bool "ST-Ericsson AB3100 Mixed Signal Circuit core functions"
 	depends on I2C=y && ABX500_CORE
+	select MFD_CORE
 	default y if ARCH_U300
 	help
 	  Select this to enable the AB3100 Mixed Signal IC core