ACPI: Do not fail acpi_bind_one() if device is already bound correctly

Modify acpi_bind_one() so that it doesn't fail if the device
represented by its first argument has already been bound to the
given ACPI handle (second argument), because that is not a good
enough reason for returning an error code.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
Acked-by: Toshi Kani <toshi.kani@hp.com>