leds: leds-qpnp: Correctly terminate of_device_id array

Add missing NULL terminator for device match table in drivers leds-qpnp.c.
Without this, of_dev_lookup() may run off the end of the array looking
for bogus data.

Change-Id: Ie6c61b4500a5fbe792e3154a761c235573c7e6bf
CRs-Fixed: 582141
Signed-off-by: Himanshu Aggarwal <haggarwa@codeaurora.org>