Use the upsteam dtb name

This is the name proposed upstream and although the patch isn't
merged yet it's in rev 15 and the name was never argued about.
2 jobs for next-dt in 1 minute and 48 seconds (queued for 3 minutes and 55 seconds)
Status Job ID Name Coverage
  Test
passed #43958
librem5
builtin_tests

00:00:50

 
  Pkg
passed #43959
librem5
build-debian-package

00:00:58