kernel/utsname_sysctl.c: Fix hostname polling

kernel/utsname_sysctl.c: Fix hostname polling

Commit bfca3dd3d068 ("kernel/utsname_sysctl.c: print kernel arch") added
a new entry to the uts_kern_table[] array, but didn't update the
UTS_PROC_xyz enumerators of older entries, breaking anything that used
them.

Which is admittedly not many cases: it's really just the two uses of
uts_proc_notify() in kernel/sys.c.  But apparently journald-systemd
actually uses this to detect hostname changes.

Reported-by: Torsten Hilbrich <[email protected]>
Fixes: bfca3dd3d068 ("kernel/utsname_sysctl.c: print kernel arch")
Link: https://lore.kernel.org/lkml/[email protected]/
Link: https://linux-regtracking.leemhuis.info/regzbot/regression/[email protected]/
Cc: Petr Vorel <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>