HID: sony: Initialize the controller LEDs with a device ID value

Add an IDA id allocator to assign unique, sequential device ids to Sixaxis and
DualShock 4 controllers.

Use the device ID to initialize the Sixaxis and DualShock 4 controller LEDs to
default values.  The number or color of the controller is set relative to other
connected Sony controllers.

Set the LED class brightness values to the initial values and add the new led to
the array before calling led_classdev_register so that the correct brightness
value shows up in the LED sysfs entry.

Use explicit module init and exit functions since the IDA allocator must be
manually destroyed when the module is unloaded.

Signed-off-by: Frank Praznik <frank.praznik@oh.rr.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>