i2c: break out ACPI support into separate file

Removes some ifdeffery. Also add the new file to the relevant
MAINTAINERS section.
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

MAINTAINERS

@@ -6273,6 +6273,7 @@ M:	Mika Westerberg <mika.westerberg@linux.intel.com>
 L:	linux-i2c@vger.kernel.org
 L:	linux-acpi@vger.kernel.org
 S:	Maintained
+F:	drivers/i2c/i2c-core-acpi.c
 
 I2C-TAOS-EVM DRIVER
 M:	Jean Delvare <jdelvare@suse.com>

drivers/i2c/Makefile

@@ -5,6 +5,7 @@
 obj-$(CONFIG_I2C_BOARDINFO)	+= i2c-boardinfo.o
 obj-$(CONFIG_I2C)		+= i2c-core.o
 i2c-core-objs 			:= i2c-core-base.o i2c-core-smbus.o
+i2c-core-$(CONFIG_ACPI)		+= i2c-core-acpi.o
 i2c-core-$(CONFIG_I2C_SLAVE) 	+= i2c-core-slave.o
 i2c-core-$(CONFIG_OF) 		+= i2c-core-of.o
 

drivers/i2c/i2c-core.h

@@ -30,6 +30,21 @@ extern int		__i2c_first_dynamic_bus_num;
 int i2c_check_addr_validity(unsigned addr, unsigned short flags);
 int i2c_check_7bit_addr_validity_strict(unsigned short addr);
 
+#ifdef CONFIG_ACPI
+void i2c_acpi_register_devices(struct i2c_adapter *adap);
+#else /* CONFIG_ACPI */
+static inline void i2c_acpi_register_devices(struct i2c_adapter *adap) { }
+#endif /* CONFIG_ACPI */
+extern struct notifier_block i2c_acpi_notifier;
+
+#ifdef CONFIG_ACPI_I2C_OPREGION
+int i2c_acpi_install_space_handler(struct i2c_adapter *adapter);
+void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter);
+#else /* CONFIG_ACPI_I2C_OPREGION */
+static inline int i2c_acpi_install_space_handler(struct i2c_adapter *adapter) { return 0; }
+static inline void i2c_acpi_remove_space_handler(struct i2c_adapter *adapter) { }
+#endif /* CONFIG_ACPI_I2C_OPREGION */
+
 #ifdef CONFIG_OF
 void of_i2c_register_devices(struct i2c_adapter *adap);
 #else