mfd: convert PASIC3 to use MFD core

This patch makes htc-pasic3 register the DS1WM and LED cell drivers
through the MFD core infrastructure instead of allocating the platform
devices manually. It also calculates the bus_shift parameter from the
memory resource size.

Signed-off-by: Philipp Zabel <philipp.zabel@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index 75f35db..ee3927a 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -52,6 +52,7 @@
 
 config HTC_PASIC3
 	tristate "HTC PASIC3 LED/DS1WM chip support"
+	select MFD_CORE
 	help
 	  This core driver provides register access for the LED/DS1WM
 	  chips labeled "AIC2" and "AIC3", found on HTC Blueangel and