ALSA: rme96: Constify hw_constraints

snd_pcm_hw_constraint_list(), *_ratnums() and *_ratdens() receive the
const pointers.  Constify the corresponding static objects for better
hardening.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/rme96.c b/sound/pci/rme96.c
index 24f1349..2e19ba5 100644
--- a/sound/pci/rme96.c
+++ b/sound/pci/rme96.c
@@ -1163,9 +1163,9 @@ snd_rme96_interrupt(int irq,
 	return IRQ_HANDLED;
 }
 
-static unsigned int period_bytes[] = { RME96_SMALL_BLOCK_SIZE, RME96_LARGE_BLOCK_SIZE };
+static const unsigned int period_bytes[] = { RME96_SMALL_BLOCK_SIZE, RME96_LARGE_BLOCK_SIZE };
 
-static struct snd_pcm_hw_constraint_list hw_constraints_period_bytes = {
+static const struct snd_pcm_hw_constraint_list hw_constraints_period_bytes = {
 	.count = ARRAY_SIZE(period_bytes),
 	.list = period_bytes,
 	.mask = 0