leds: leds-lp50xx: Allow LED 0 to be added to module bank

leds: leds-lp50xx: Allow LED 0 to be added to module bank

led_banks contains LED module number(s) that should be grouped into the
module bank. led_banks is 0-initialized.
By checking the led_banks entries for 0, un-set entries are detected.
But a 0-entry also indicates that LED module 0 should be grouped into the
module bank.

By only iterating over the available entries no check for unused entries
is required and LED module 0 can be added to bank.

Cc: stable@vger.kernel.org
Fixes: 242b81170fb8 ("leds: lp50xx: Add the LP50XX family of the RGB LED driver")
Signed-off-by: Christian Hitz <christian.hitz@bbv.ch>
Reviewed-by: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Link: https://patch.msgid.link/20251008123222.1117331-1-christian@klarinett.li
Signed-off-by: Lee Jones <lee@kernel.org>