tree-wide: drop printk.devkmsg=on setting in various places

Since 6123dfaa72 this should not be necessary anymore.

.mkosi/mkosi.fedora

@@ -10,7 +10,6 @@ Release=31
 [Output]
 Format=gpt_ext4
 Bootable=yes
-KernelCommandLine=printk.devkmsg=on
 
 [Partitions]
 RootSize=3G

man/journald.conf.xml

@@ -350,9 +350,9 @@
         <varname>TTYPath=</varname>, described below.</para>
 
         <para>When forwarding to the kernel log buffer (kmsg), make sure to select a suitably large size for
-        the log buffer, and ensure the kernel's rate-limiting applied to userspace processes is turned
-        off. Specifically, add <literal>log_buf_len=8M</literal> and <literal>printk.devkmsg=on</literal> (or
-        similar) to the kernel command line.</para></listitem>
+        the log buffer, for example by adding <literal>log_buf_len=8M</literal> to the kernel command line.
+        <command>systemd</command> will automatically disable kernel's rate-limiting applied to userspace
+        processes (equivalent to setting <literal>printk.devkmsg=on</literal>).</para></listitem>
       </varlistentry>
 
       <varlistentry>

test/mkosi.default.networkd-test

@@ -10,7 +10,6 @@ Release=29
 [Output]
 Format=raw_btrfs
 Bootable=yes
-KernelCommandLine=printk.devkmsg=on
 OutputDirectory=../mkosi.output
 Output=networkd-test.raw
 

test/test-functions

@@ -212,7 +212,6 @@ loglevel=2 \
 init=$PATH_TO_INIT \
 console=$CONSOLE \
 selinux=0 \
-printk.devkmsg=on \
 $_cgroup_args \
 $KERNEL_APPEND \
 "