mfd: New AB8500 driver

Add a new driver to support the AB8500 Power Management chip, replacing
the current AB4500.  The new driver replaces the old one, instead of an
incremental modification, because this is a substantial overhaul
including:

 - Split of the driver into -core and -spi portions, to allow another
   interface layer to be added

 - Addition of interrupt support

 - Switch to MFD core API for handling subdevices

 - Simplification of the APIs to remove a redundant block parameter

 - Rename of the APIs and macros from ab4500_* to ab8500_*

 - Rename of the files from ab4500* to ab8500*

 - Change of the driver name from ab4500 to ab8500

Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index b84b707..9da0e50 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -420,11 +420,12 @@
 	  This enables the PCAP ASIC present on EZX Phones. This is
 	  needed for MMC, TouchScreen, Sound, USB, etc..
 
-config AB4500_CORE
-	tristate "ST-Ericsson's AB4500 Mixed Signal Power management chip"
-	depends on SPI
+config AB8500_CORE
+	bool "ST-Ericsson AB8500 Mixed Signal Power Management chip"
+	depends on SPI=y && GENERIC_HARDIRQS
+	select MFD_CORE
 	help
-	  Select this option to enable access to AB4500 power management
+	  Select this option to enable access to AB8500 power management
 	  chip. This connects to U8500 on the SSP/SPI bus and exports
 	  read/write functions for the devices to get access to this chip.
 	  This chip embeds various other multimedia funtionalities as well.