staging: lustre: fixed const warnings (struct seq_operations should be const in these contexts)

Minor warnings spotted by checkpatch.pl in lustre regarding const correctness: struct seq_operations should be const.
Signed-off-by: Xavier Roche <roche+git@httrack.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/vvp_dev.c

@@ -517,7 +517,7 @@ static void vvp_pgcache_stop(struct seq_file *f, void *v)
 	/* Nothing to do */
 }
 
-static struct seq_operations vvp_pgcache_ops = {
+static const struct seq_operations vvp_pgcache_ops = {
 	.start = vvp_pgcache_start,
 	.next  = vvp_pgcache_next,
 	.stop  = vvp_pgcache_stop,

drivers/staging/lustre/lustre/lmv/lproc_lmv.c

@@ -177,7 +177,7 @@ static int lmv_tgt_seq_show(struct seq_file *p, void *v)
 	return 0;
 }
 
-static struct seq_operations lmv_tgt_sops = {
+static const struct seq_operations lmv_tgt_sops = {
 	.start		 = lmv_tgt_seq_start,
 	.stop		  = lmv_tgt_seq_stop,
 	.next		  = lmv_tgt_seq_next,

drivers/staging/lustre/lustre/lov/lov_pool.c

@@ -268,7 +268,7 @@ static int pool_proc_show(struct seq_file *s, void *v)
 	return 0;
 }
 
-static struct seq_operations pool_proc_ops = {
+static const struct seq_operations pool_proc_ops = {
 	.start	  = pool_proc_start,
 	.next	   = pool_proc_next,
 	.stop	   = pool_proc_stop,