arm64: dts: imx8mq-librem5: add flash-leds to the rear cam

2 jobs for led_flash in 65 minutes and 49 seconds (queued for 1 second)
latest
Status Job ID Name Coverage
  Build
passed #366141
librem5
build:aarch64

00:19:54

passed #366142
librem5:arm64
build:deb

01:05:49