i2c: move acpi code back into the core

Commit 5d98e61d337c ("I2C/ACPI: Add i2c ACPI operation region support")
renamed the i2c-core module. This may cause regressions for
distributions, so put the ACPI code back into the core.

Reported-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Tested-by: Lan Tianyu <tianyu.lan@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
index e0228b2..1722f50 100644
--- a/drivers/i2c/Makefile
+++ b/drivers/i2c/Makefile
@@ -2,11 +2,8 @@
 # Makefile for the i2c core.
 #
 
-i2ccore-y := i2c-core.o
-i2ccore-$(CONFIG_ACPI)	 	+= i2c-acpi.o
-
 obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
-obj-$(CONFIG_I2C)		+= i2ccore.o
+obj-$(CONFIG_I2C)		+= i2c-core.o
 obj-$(CONFIG_I2C_SMBUS)		+= i2c-smbus.o
 obj-$(CONFIG_I2C_CHARDEV)	+= i2c-dev.o
 obj-$(CONFIG_I2C_MUX)		+= i2c-mux.o