mfd: Align ab8500 with the abx500 interface

This patch makes the ab8500 mixed signal chip expose the same
interface for register access as the ab3100, ab3550 and ab5500 chip.
The ab8500_read() and ab8500_write() is removed and replaced with
abx500_get_register_interruptible() and
abx500_set_register_interruptible().

Signed-off-by: Mattias Wallin <mattias.wallin@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/mfd/abx500.h b/include/linux/mfd/abx500.h
index 390726f..be7373c 100644
--- a/include/linux/mfd/abx500.h
+++ b/include/linux/mfd/abx500.h
@@ -6,8 +6,7 @@
  *
  * ABX500 core access functions.
  * The abx500 interface is used for the Analog Baseband chip
- * ab3100, ab3550, ab5500 and possibly comming. It is not used for
- * ab4500 and ab8500 since they are another family of chip.
+ * ab3100, ab3550, ab5500, and ab8500.
  *
  * Author: Mattias Wallin <mattias.wallin@stericsson.com>
  * Author: Mattias Nilsson <mattias.i.nilsson@stericsson.com>