debian/control: fix the debian control file

Fix lintian warnings

Signed-off-by: Angus Ainslie <angus@akkea.ca>
5 jobs for pureos/byzantium in 1 minute and 44 seconds (queued for 1 second)
Status Name Job ID Coverage
  Package
passed package-pureos-byzantium #366672
librem5

00:00:38

passed package-pureos-byzantium:arm64 #366673
librem5:arm64

00:01:44

 
  Test Package
passed autopkgtest-pureos-byzantium-package #366674
librem5

00:00:48

passed check-tarball #366676
librem5

00:00:49

passed lintian-pureos-byzantium-package #366675
librem5

00:00:43