ACPI / APD: Add APM X-Gene ACPI I2C device support

Add APM X-Gene ACPI I2C device support by hooks into existent
ACPI APD driver.  To fully enable support, require another
patch to add the X-Gene ACPI node into the DW I2C driver.

Signed-off-by: Loc Ho <lho@apm.com>
Reviewed-by: Ken Xue <Ken.Xue@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>