ipq40xx: re-add LEDS_LP5523 for the ASUS Lyra MAP-AC2200

ipq40xx: re-add LEDS_LP5523 for the ASUS Lyra MAP-AC2200

This symbol had been enabled in the initial device support submission
for kernel 4.14, but apparently got lost during the v4.19 port.

The ASUS Lyra MAP-AC2200 has a single (very bright) rgb LED, which is
controlled by the TI/National LP5523/55231 LED driver chip. It is left
enabled in a pulsating infinite rainbow loop by the bootloader,
expecting it to be reconfigured (disabled by default) after the boot
process has finished and is also required to indicate failsafe/
firstboot conditions.

Signed-off-by: Stefan Lippers-Hollmann <s.l-h@gmx.de>