leds: ip30: compile if COMPILE_TEST=y

This driver can be compiled on other platforms with small change if
COMPILE_TEST=y.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Dan Murphy <dmurphy@ti.com>
Cc: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Signed-off-by: Pavel Machek <pavel@ucw.cz>