net: Keep vertical alignment

Those files under /proc/net/stat/ don't have vertical alignment, it looks
very difficult. Modify the seq_printf statement, keep vertical alignment.

v2:
 - Use seq_puts() and seq_printf() correctly.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/neighbour.c

@@ -3315,12 +3315,13 @@ static int neigh_stat_seq_show(struct seq_file *seq, void *v)
 	struct neigh_statistics *st = v;
 
 	if (v == SEQ_START_TOKEN) {
-		seq_printf(seq, "entries  allocs destroys hash_grows  lookups hits  res_failed  rcv_probes_mcast rcv_probes_ucast  periodic_gc_runs forced_gc_runs unresolved_discards table_fulls\n");
+		seq_puts(seq, "entries  allocs   destroys hash_grows lookups  hits     res_failed rcv_probes_mcast rcv_probes_ucast periodic_gc_runs forced_gc_runs unresolved_discards table_fulls\n");
 		return 0;
 	}
 
 	seq_printf(seq, "%08x %08lx %08lx %08lx   %08lx %08lx %08lx   "
-			"%08lx %08lx  %08lx %08lx %08lx %08lx\n",
+			"%08lx         %08lx         %08lx         "
+			"%08lx       %08lx            %08lx\n",
 		   atomic_read(&tbl->entries),
 
 		   st->allocs,

net/ipv4/route.c

@@ -276,12 +276,13 @@ static int rt_cpu_seq_show(struct seq_file *seq, void *v)
 	struct rt_cache_stat *st = v;
 
 	if (v == SEQ_START_TOKEN) {
-		seq_printf(seq, "entries  in_hit in_slow_tot in_slow_mc in_no_route in_brd in_martian_dst in_martian_src  out_hit out_slow_tot out_slow_mc  gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
+		seq_puts(seq, "entries  in_hit   in_slow_tot in_slow_mc in_no_route in_brd   in_martian_dst in_martian_src out_hit  out_slow_tot out_slow_mc gc_total gc_ignored gc_goal_miss gc_dst_overflow in_hlist_search out_hlist_search\n");
 		return 0;
 	}
 
-	seq_printf(seq,"%08x  %08x %08x %08x %08x %08x %08x %08x "
-		   " %08x %08x %08x %08x %08x %08x %08x %08x %08x \n",
+	seq_printf(seq, "%08x %08x %08x    %08x   %08x    %08x %08x       "
+			"%08x       %08x %08x     %08x    %08x %08x   "
+			"%08x     %08x        %08x        %08x\n",
 		   dst_entries_get_slow(&ipv4_dst_ops),
 		   0, /* st->in_hit */
 		   st->in_slow_tot,